APPENDIX TO: HAVE HEMOPHILIACS EVER BEEN AT RISK FOR HIV INFECTION THROUGH FACTOR VIII? A curious correspondence between HEAL Toronto and the Center for Disease Control and Prevention (CDC), U.S.A.. They confirm that HIV could not have been transmitted to people with haemophilia via transfusions of clotting factor. The CDC attached a file containing numerous CDC publications, all with variations of the "essentially zero" quotation:
CDC National AIDS Hotline Training Bulletin #101
Centers for Disease Control and Prevention
Statement Concerning HIV and Its Transmission
May 25, 1994
This is a statement from the Centers for Disease Control and
Prevention (CDC) concerning the human immunodeficiency virus (HIV)
and its transmission. (Update of Hotline Training Bulletin #25.)
Research has revealed a great deal of valuable medical, scientific,
and public health information about the human immunodeficiency
virus (HIV) and acquired immunodeficiency syndrome (AIDS). The
ways in which HIV can be transmitted have been clearly identified.
Unfortunately, some widely dispersed information does not reflect
the conclusions of scientific findings. The Centers for Disease
Control and Prevention (CDC) provides the following information to
help correct a few commonly held misperceptions about HIV.
Transmission
HIV is spread by sexual contact with an infected person, by
needle-sharing among injecting drug users, or, less commonly (and
now very rarely in countries where blood is screened for HIV
antibodies), through transfusions of infected blood or blood
clotting factors. Babies born to HIV-infected women may become
infected before or during birth, or through breast-feeding after
birth.
In the health-care setting, workers have been infected with HIV
after being stuck with needles containing HIV-infected blood or,
less frequently, after infected blood gets into the workerþs
bloodstream through an open cut or splashes into a mucous membrane
(e.g., eyes or inside of the nose). There has been only one
demonstrated instance of patients being infected by a health-care
worker; this involved HIV transmission from an infected dentist to
six patients. Investigations have been completed involving more
than 22,000 patients of 63 HIV-infected doctors and dentists, and
no other cases of this type of transmission have been identified.
Some people fear that HIV might be transmitted in other ways;
however, no scientific evidence to support any of these fears has
been found. If HIV were being transmitted through other routes
(for example, through air or insects), the pattern of reported AIDS
cases would be much different from what has been observed, and
cases would be occurring much more frequently in persons who report
no identified risk for infection. All reported cases suggesting
new or potentially unknown routes of transmission are promptly and
thoroughly investigated by state and local health departments with
the assistance, guidance, and laboratory support from CDC; no
additional routes of transmission have been recorded, despite a
national sentinel system designed to detect just such an
occurrence.
The following paragraphs specifically address some of the more
common misperceptions about HIV transmission.
HIV in the Environment
Scientists and medical authorities agree that HIV does not survive
well in the environment, making the possibility of environmental
transmission remote. HIV is found in varying concentrations or
amounts in blood, semen, vaginal fluid, breast milk, saliva, and
tears. (See page 3, Saliva, Tears, and Sweat.) In order to obtain
data on the survival of HIV, laboratory studies have required the
use of artificially high concentrations of laboratory-grown virus.
Although these unnatural concentrations of HIV can be kept alive
under precisely controlled and limited laboratory conditions, CDC
studies have shown that drying of even these high concentrations of
HIV reduces the number of infectious viruses by 90 to 99 percent
within several hours. Since the HIV concentrations used in
laboratory studies are much higher than those actually found in
blood or other specimens, drying of HIV-infected human blood or
other body fluids reduces the theoretical risk of environmental
transmission to that which has been observedþþessentially zero.
Incorrect interpretation of conclusions drawn from laboratory
studies have alarmed people unnecessarily. Results from laboratory
studies should not be used to determine specific personal risk of
infection because 1) the amount of virus studied is not found in
human specimens or anyplace else in nature, and 2) no one has been
identified as infected with HIV due to contact with an
environmental surface. Additionally, since HIV is unable to
reproduce outside its living host (unlike many bacteria or fungi,
which may do so under suitable conditions), except under laboratory
conditions, it does not spread or maintain infectiousness outside
its host.
Households and Other Settings
Although HIV has been transmitted between family members in a
household setting, this type of transmission is very rare. These
transmissions are believed to have resulted from contact between
skin or mucous membranes and infected blood or body fluids. To
prevent even such rare occurrences, precautions, as described in
previously published guidelines, should be taken in all
settingsþþincluding the homeþþto prevent exposures to the blood or
body fluids of persons who are HIV infected, at risk for HIV
infection, or whose infection and risk status are unknown. For
example, gloves should be worn during contact with blood or other
body fluids that could possibly contain blood, such as urine,
feces, or vomit. Cuts, sores, or breaks on both the caregiver's
and patient's exposed skin should be covered with bandages. Hands
and other parts of the body should be washed immediately after
contact with blood or other body fluids, and surfaces soiled with
blood should be disinfected appropriately. Practices that increase
the likelihood of blood contact, such as sharing of razors and
toothbrushes, should be avoided. Needles and other sharp
instruments should be used only when medically necessary and
handled according to recommendations for health-care settings. (Do
not put caps back on needles by hand or remove needles from
syringes. Dispose of needles in puncture-proof containers out of
the reach of children and visitors.)
There is no known risk of HIV transmission to co-workers, clients,
or consumers from contact in industries such as food service
establishments (see information on survival of HIV in the
environment). Food service workers known to be infected with HIV
need not be restricted from work unless they have other infections
or illnesses (such as diarrhea or hepatitis A) for which any food
service worker, regardless of HIV infection status, should be
restricted. The Public Health Service recommends that all food
service workers follow recommended standards and practices of good
personal hygiene and food sanitation.
In 1985, CDC issued routine precautions that all personal service
workers (e.g., hairdressers, barbers, cosmetologists, massage
therapists) should follow, even though there is no evidence of
transmission from a personal service worker to a client or vice
versa. Instruments that are intended to penetrate the skin (e.g.,
tattooing and acupuncture needles, ear piercing devices) should be
used once and disposed of or thoroughly cleaned and sterilized
after each use using procedures recommended for use in health-care
institutions. Instruments not intended to penetrate the skin but
which may become contaminated with blood (e.g., razors) should be
used for only one client and disposed of or thoroughly cleaned and
disinfected after each use.
Kissing
Casual contact through closed-mouth or þsocialþ kissing is not a
risk for transmission of HIV. Because of the theoretical
potential for contact with blood during þFrenchþ or open-mouthed
kissing, CDC recommends against engaging in this activity with an
infected person. However, no case of AIDS reported to CDC can be
attributed to transmission through any kind of kissing.
Saliva, Tears, and Sweat
HIV has been found in saliva and tears in only minute quantities
from some AIDS patients. It is important to understand that
finding a small amount of HIV in a body fluid does not
necessarily mean that HIV can be transmitted by that body fluid.
HIV has not been recovered from the sweat of HIV-infected
persons. Contact with saliva, tears, or sweat has never been
shown to result in transmission of HIV.
Insects
From the onset of the HIV epidemic, there has been concern about
transmission of the virus by biting and blood-sucking insects.
However, studies conducted by researchers at CDC and elsewhere
have shown no evidence of HIV transmission through insectsþþeven
in areas where there are many cases of AIDS and large populations
of insects such as mosquitoes. Lack of such outbreaks, despite
intense efforts to detect them, supports the conclusion that HIV
is not transmitted by insects.
The results of experiments and observations of insect biting
behavior indicate that when an insect bites a person, it does not
inject its own or a previous victimþs blood into the new victim.
Rather, it injects saliva. Such diseases as yellow fever and
malaria are transmitted through the saliva of specific species of
mosquitoes. However, HIV lives for only a short time inside an
insect and, unlike organisms that are transmitted via insect
bites, HIV does not reproduce (and, therefore, cannot survive) in
insects. Thus, even if the virus enters a mosquito or another
sucking or biting insect, the insect does not become infected and
cannot transmit HIV to the next human it feeds on or bites.
There is also no reason to fear that a biting or blood-sucking
insect, such as a mosquito, could transmit HIV from one person to
another through HIV-infected blood left on its mouth parts. Two
factors combine to make infection by this route extremely
unlikelyþþfirst, infected people do not have constant, high
levels of HIV in their bloodstreams and, second, insect mouth
parts do not retain large amounts of blood on their surfaces.
Further, scientists who study insects have determined that biting
insects normally do not travel from one person to the next
immediately after ingesting blood.
Effectiveness of Condoms
The proper and consistent use of latex condoms when engaging in
sexual intercourseþþvaginal, anal, or oralþþcan greatly reduce a
personþs risk of acquiring or transmitting sexually transmitted
diseases, including HIV infection.
Under laboratory conditions, viruses occasionally have been shown
to pass through natural membrane (þskinþ or lambskin) condoms,
which contain natural pores and are therefore not recommended for
disease prevention. On the other hand, laboratory studies have
consistently demonstrated that latex condoms provide a highly
effective mechanical barrier to HIV.
In order for condoms to provide maximum protection, they must be
used consistently (every time) and correctly. Incorrect use
contributes to the possibility that the condom could leak or
break. Proper use should include the following:
þ Put on the condom as soon as erection occurs and before
any sexual contact (vaginal, anal, or oral).
þ Leave space at the tip of the condom.
þ Use only water-based lubricants. (Oil-based lubricants
can weaken the condom.)
þ Hold the condom firmly to keep it from slipping off and
withdraw from the partner immediately after
ejaculation.
When condoms are used reliably, they have been shown to prevent
pregnancy up to 98 percent of the time among couples using them
as their only method of contraception. Similarly, numerous
studies among sexually active people have demonstrated that a
properly used latex condom provides a high degree of protection
against a variety of sexually transmitted diseases, including HIV
infection.
Condoms are classified as medical devices and are regulated by
the Food and Drug Administration. Condom manufacturers in the
United States test each latex condom for defects, including
holes, before it is packaged. Several studies of actual condom
usage clearly show that condom breakage rates in this country are
less than 2 percent. Even when condoms do break, one study
showed that more than half of such breaks occurred prior to
ejaculation.
Latex condoms can provide a high degree of protection against
pregnancy and most sexually transmitted diseases, including HIV
infection, but only if they are used consistently and correctly.
For more detailed information about condoms, see CDC's þFacts
About... The Role of Condoms in Preventing HIV Infection and
Other Sexually Transmitted Diseases.þ
The Public Health Service Response
The U.S. Public Health Service is committed to providing the
scientific community and the public with accurate and objective
information about HIV infection and AIDS. It is vital that clear
information on HIV infection and AIDS be readily available to
help prevent further transmission of the virus and to allay fears
and prejudices caused by misinformation. For a complete
description of CDC's HIV/AIDS prevention programs, see "Facts
about... The Centers for Disease Control and Prevention's (CDC)
HIV/AIDS Prevention Activities."
CDC NATIONAL AIDS HOTLINE TRAINING BULLETIN #25
Centers for Disease Control and Prevention
Statement on HIV Transmission
February 22, 1993
This is a statement from the Centers for Disease Control and
Prevention (CDC) concerning the transmission of HIV.
Research has revealed a great deal of valuable medical,
scientific, and public health information about the human
immunodeficiency virus (HIV) and acquired immunodeficiency
syndrome (AIDS). The ways in which HIV can be transmitted
have been clearly identified. Unfortunately, some widely
dispersed information does not reflect the conclusions of
scientific findings. The Centers for Disease Control and
Prevention (CDC) provides the following information to help
correct a few commonly held misperceptions about HIV.
Transmission
HIV is spread by sexual contact with an infected person, by
needle-sharing among injecting drug users, or, less commonly
(and now very rarely in countries where blood is screened for
HIV antibodies), through transfusions of infected blood or
blood clotting factors. Babies born to HIV-infected women may
become infected before or during birth, or through
breast-feeding after birth.
In the health-care setting, workers have been infected with
HIV after being stuck with needles containing HIV-infected
blood or, less frequently, after infected blood gets into the
workers bloodstream through an open cut or splashes into a
mucous membrane (e.g., eyes or inside of the nose). There has
been only one demonstrated instance of patients being infected
by a health-care worker; this involved HIV transmission from
an infected dentist to five patients. Investigations have
been completed involving more than 15,000 patients of 32
HIV-infected doctors and dentists, and no other cases of this
type of transmission have been identified.
Some people fear that HIV might be transmitted in other ways;
however, no scientific evidence to support any of these fears
has been found. If HIV were being transmitted through other
routes (for example, through air or insects), the pattern of
reported AIDS cases would be much different from what has been
observed, and cases would be occurring much more frequently in
persons who report no identified risk for infection. All
reported cases suggesting new or potentially unknown routes of
transmission are promptly and thoroughly investigated by state
and local health departments with the assistance, guidance,
and laboratory support from CDC; no additional routes of
transmission have been recorded, despite a national sentinel
system designed to detect just such an occurrence.
The following paragraphs specifically address some of the more
common misperceptions about HIV transmission.
HIV in the Environment
Scientists and medical authorities agree that HIV does not
survive well in the environment, making the possibility of
environmental transmission remote. HIV is found in varying
concentrations or amounts in blood, semen, vaginal fluid,
breast milk, saliva, and tears. (See page 3, Saliva, Tears,
and Sweat.) In order to obtain data on the survival of HIV,
laboratory studies have required the use of artificially high
concentrations of laboratory-grown virus. Although these
unnatural concentrations of HIV can be kept alive
under precisely controlled and limited laboratory conditions,
CDC studies have shown that drying of even these high
concentrations of HIV reduces the number of infectious viruses
by 90 to 99 percent within several hours. Since the HIV
concentrations used in laboratory studies are much higher than
those actually found in blood or other specimens, drying of
HIV-infected human blood or other body fluids reduces the
theoretical risk of environmental transmission to that which
has been observed--essentially zero. Incorrect interpretation
of conclusions drawn from laboratory studies have alarmed
people unnecessarily. Results from laboratory studies should
not be used to determine specific personal risk of infection
because 1) the amount of virus studied is not found in
human specimens or anyplace else in nature, and 2) no one has
been identified as infected with HIV due to contact with an
environmental surface. Additionally, since HIV is unable to
reproduce outside its living host (unlike many bacteria or
fungi, which may do so under suitable conditions), except
under laboratory conditions, it does not spread or maintain
infectiousness outside its host.
Households, Offices, and Workplaces
Studies of thousands of households where families have lived
with and cared for AIDS patients have found no instances of
nonsexual transmission, despite the sharing of kitchen,
laundry, and bathroom facilities, meals, eating utensils, and
drinking cups and glasses. If HIV is not transmitted in these
settings, where repeated and prolonged contact occurs,
transmission is even less likely in other
settings, such as schools and offices.
Similarly, there is no known risk of HIV transmission to
co-workers, clients, or consumers from contact in industries
such as food service establishments (see information on
survival of HIV in the environment). Food service workers
known to be infected with HIV need not be restricted from work
unless they have other infections or illnesses (such as
diarrhea or hepatitis A) for which any food service worker,
regardless of HIV infection status, should be restricted. The
Public Health Service recommends that all food service workers
follow recommended standards and practices of good
personal hygiene and food sanitation.
Kissing
Casual contact through closed-mouth or social kissing is not
a risk for transmission of HIV. Because of the theoretical
potential for contact with blood during French or open-mouthed
kissing, CDC recommends against engaging in this activity with
an infected person. However, no case of AIDS reported to CDC
can be attributed to transmission through any kind of kissing.
Saliva, Tears, and Sweat
HIV has been found in saliva and tears in only minute
quantities from some AIDS patients. It is important to
understand that finding a small amount of HIV in a body fluid
does not necessarily mean that HIV can be transmitted by that
body fluid. HIV has not been recovered from the sweat of
HIV-infected persons. Contact with saliva, tears, or sweat
has never been shown to result in transmission of HIV.
Insects
From the onset of the HIV epidemic, there has been concern
about transmission of the virus by biting and blood-sucking
insects. However, studies conducted by researchers at CDC and
elsewhere have shown no evidence of HIV transmission through
insects--even in areas where there are many cases of AIDS and
large populations of insects such as mosquitoes. Lack of such
outbreaks, despite intense efforts to detect them, supports
the conclusion that HIV is not transmitted by insects.
The results of experiments and observations of insect biting
behavior indicate that when an insect bites a person, it does
not inject its own or a previous victim's blood into the new
victim. Rather, it injects saliva. Such diseases as yellow
fever and malaria are transmitted through the saliva of
specific species of mosquitoes. However, HIV lives for only
a short time inside an insect and, unlike organisms that are
transmitted via insect bites, HIV does not reproduce (and,
therefore, cannot survive) in insects. Thus, even if the virus
enters a mosquito or another sucking or biting insect, the
insect does not become infected and cannot
transmit HIV to the next human it feeds on or bites.
There is also no reason to fear that a biting or blood-sucking
insect, such as a mosquito, could transmit HIV from one person
to another through HIV-infected blood left on its mouth parts.
Two factors combine to make infection by this route extremely
unlikely--first, infected people do not have constant, high
levels of HIV in their bloodstreams and, second, insect mouth
parts do not retain large amounts of blood on their surfaces.
Further, scientists who study insects have
determined that biting insects normally do not travel from one
person to the next immediately after ingesting blood.
Effectiveness of Condoms
The proper and consistent use of latex condoms when engaging
in sexual intercourse--anal, vaginal, or oral--can greatly
reduce a person's risk of acquiring or transmitting sexually
transmitted diseases, including HIV infection.
Under laboratory conditions, viruses occasionally have been
shown to pass through natural membrane (skin or lambskin)
condoms, which contain natural pores and are therefore not
recommended for disease prevention. On the other hand,
laboratory studies have consistently demonstrated that latex
condoms provide a highly effective mechanical barrier to HIV.
In order for condoms to provide maximum protection, they must
be used consistently (every time) and correctly. Incorrect
use contributes to the possibility that the condom could leak
or break. Proper use should include the following:
* Put on the condom as soon as erection occurs and before
any sexual contact (anal, vaginal, or oral).
* Leave space at the tip of the condom.
* Use only water-based lubricants. (Oil-based lubricants
can weaken the condom.)
* Hold the condom firmly to keep it from slipping off and
withdraw from the partner immediately after ejaculation.
When condoms are used reliably, they have been shown to
prevent pregnancy up to 98 percent of the time among couples
using them as their only method of contraception. Similarly,
numerous studies among sexually active people have
demonstrated that a properly used latex condom provides a high
degree of protection against a variety of sexually transmitted
diseases, including HIV infection.
Condoms are classified as medical devices and are regulated by
the Food and Drug Administration. Each latex condom
manufactured in the United States is tested for defects,
including holes, before it is packaged, and several studies
clearly show that condom breakage rates in this country are
less than 2 percent. Even when condoms do break, one study
showed that more than half of such breaks occurred prior to
ejaculation.
Latex condoms can provide up to 98-99 percent protection
against pregnancy and most sexually transmitted diseases,
including HIV infection, but only if they are used
CONSISTENTLY and CORRECTLY.
For more detailed information about condoms, see CDC's fact
sheet, "The Role of Condoms in Preventing HIV Infection and
Other Sexually Transmitted Diseases."
HIV / AIDS PREVENTION FACTSHEET
Centers for Disease Control and Prevention
Facts About...The Human Immunodeficiency Virus and Its Transmission
February 1993
Research has revealed a great deal of valuable medical,
scientific, and public health information about the human
immunodeficiency virus (HIV) and acquired immunodeficiency
syndrome (AIDS). The ways in which HIV can be transmitted
have been clearly identified. Unfortunately, some widely
dispersed information does not reflect the conclusions of
scientific findings. The Centers for Disease Control and
Prevention (CDC) provides the following information to help
correct a few commonly held misperceptions about HIV.
Transmission
HIV is spread by sexual contact with an infected person, by
needle-sharing among injecting drug users, or, less commonly
(and now very rarely in countries where blood is screened for
HIV antibodies), through transfusions of infected blood or
blood clotting factors. Babies born to HIV-infected women may
become infected before or during birth, or through
breast-feeding after birth.
In the health-care setting, workers have been infected with
HIV after being stuck with needles containing HIV-infected
blood or, less frequently, after infected blood gets into the
worker's bloodstream through an open cut or splashes into a
mucous membrane (e.g., eyes or inside of the nose). There has
been only one demonstrated instance of patients being infected
by a health-care worker; this involved HIV transmission from
an infected dentist to five patients. Investigations have
been completed involving more than 15,000 patients of 32
HIV-infected doctors and dentists, and
no other cases of this type of transmission have been
identified.
Some people fear that HIV might be transmitted in other ways;
however, no scientific evidence to support any of these fears
has been found. If HIV were being transmitted through other
routes (for example, through air or insects), the pattern of
reported AIDS cases would be much different from what has been
observed, and cases would be occurring much more frequently in
persons who report no identified risk for infection. All
reported cases suggesting new or potentially unknown routes of
transmission are promptly and thoroughly investigated by state
and local health departments with the assistance, guidance,
and laboratory support from CDC; no additional routes of
transmission have been recorded, despite a
national sentinel system designed to detect just such an
occurrence.
The following paragraphs specifically address some of the more
common misperceptions about HIV transmission.
HIV in the Environment
Scientists and medical authorities agree that HIV does not
survive well in the environment, making the possibility of
environmental transmission remote. HIV is found in varying
concentrations or amounts in blood, semen, vaginal fluid,
breast milk, saliva, and tears. (See below, Saliva, Tears,
and Sweat.) In order to obtain data on the survival of HIV,
laboratory studies have required the use of artificially high
concentrations of laboratory-grown virus. Although these
unnatural concentrations of HIV can be kept alive under
precisely controlled and limited laboratory conditions, CDC
studies have shown that drying of even these high
concentrations of HIV reduces the number of infectious
viruses by 90 to 99 percent within several hours. Since the
HIV concentrations used in laboratory studies are much higher
than those actually found in blood or other specimens, drying
of HIV-infected human blood or other body fluids reduces the
theoretical risk of environmental transmission to that which
has been observed--essentially zero. Incorrect interpretation
of conclusions drawn from laboratory studies have alarmed
people unnecessarily. Results from laboratory studies should
not be used to determine specific personal risk of infection
because 1) the amount of virus studied is not found in human
specimens or anyplace else in nature, and 2) no one has been
identified with HIV due to contact with an environmental
surface; Additionally, since HIV is unable to
reproduce outside its living host (unlike many bacteria or
fungi, which may do so under suitable conditions), except
under laboratory conditions, it does not spread or maintain
infectiousness outside its host.
Households, Offices, and Workplaces
Studies of thousands of households where families have lived
with and cared for AIDS patients have found no instances of
nonsexual transmission, despite the sharing of kitchen,
laundry, and bathroom facilities, meals, eating utensils, and
drinking cups and glasses. If HIV is not transmitted in these
settings, where repeated and prolonged contact occurs,
transmission is even less likely in other settings, such as
schools and offices.
Similarly, there is no known risk of HIV transmission to co-
workers, clients, or consumers from contact in industries such
as food service establishments (see information on survival of
HIV in the environment). Food service workers known to be
infected with HIV need not be restricted from work unless they
have other infections or illnesses (such as diarrhea or
hepatitis A) for which any food service worker, regardless of
HIV infection status, should be restricted; The Public Health
Service recommends that all food service workers follow
recommended standards and practices of good personal hygiene
and food sanitation.
Kissing
Casual contact through closed-mouth or "social" kissing is not
a risk for transmission of HIV. Because of the theoretical
potential for contact with blood during "French" or
open-mouthed kissing, CDC recommends against engaging in this
activity with an infected person. However, no case of AIDS
reported to CDC can be attributed to transmission through any
kind of kissing.
Saliva, Tears, and Sweat
HIV has been found in saliva and tears in only minute
quantities from some AIDS patients. It is important to
understand that finding a small amount of HIV in a body fluid
does not necessarily mean that HIV can be transmitted by that
body fluid. HIV has not been recovered from the sweat of
HIV-infected persons. Contact with saliva, tears, or sweat has
never been shown to result in transmission of HIV.
Insects
From the onset of the HIV epidemic, there has been concern
about transmission of the virus by biting and blood-sucking
insects. However, studies conducted by researchers at CDC and
elsewhere have shown no evidence of HIV transmission through
insects--even in areas where there are many cases of AIDS and
large populations of insects such as mosquitoes. Lack of such
outbreaks, despite intense efforts to detect them, supports
the conclusion that HIV is not transmitted by insects.
The results of experiments and observations of insect biting
behavior indicate that when an insect bites a person, it does
not inject its own or a previous victim's blood into the new
victim. Rather, it injects saliva. Such diseases as yellow
fever and malaria are transmitted through the saliva of
specific species of mosquitoes. However, HIV lives for only
a short time inside an insect and, unlike organisms that are
transmitted via insect bites, HIV does not reproduce (and,
therefore, cannot survive) in insects. Thus, even if the virus
enters a mosquito or another sucking or biting insect, the
insect does not become infected and cannot transmit HIV to the
next human it feeds on or bites.
There is also no reason to fear that a biting or blood-sucking
insect, such as a mosquito, could transmit HIV from one person
to another through HIV-infected blood left on its mouth parts.
Two factors combine to make infection by this route extremely
unlikely--first, infected people do not have constant, high
levels of HIV in their bloodstreams and, second, insect mouth
parts do not retain large amounts of blood on their surfaces.
Further, scientists who study insects have determined that
biting insects normally do not travel from one person to the
next immediately after ingesting blood.
Effectiveness of Condoms
The proper and consistent use of latex condoms when engaging
in sexual intercourse--vaginal, anal, or oral--can greatly
reduce a person's risk of acquiring or transmitting sexually
transmitted diseases, including HIV infection.
Under laboratory conditions, viruses occasionally have been
shown to pass through natural membrane ("skin" or lambskin)
condoms, which contain natural pores and are therefore not
recommended for disease prevention. On the other hand,
laboratory studies have consistently demonstrated that latex
condoms provide a highly effective mechanical barrier to HIV.
In order for condoms to provide maximum protection, they must
be used consistently (every time) and correctly. Incorrect
use contributes to the possibility that the condom could leak
or break. Proper use should include the following:
* Put on the condom as soon as erection occurs and before any
sexual contact (vaginal, anal, or oral).
* Leave space at the tip of the condom.
* Use only water-based lubricants. (Oil-based lubricants can
weaken the condom.)
* Hold the condom firmly to keep it from slipping off and
withdraw from the partner immediately after ejaculation.
When condoms are used reliably, they have been shown to
prevent pregnancy up to 98 percent of the time among couples
using them as their only method of contraception. Similarly,
numerous studies among sexually active people have
demonstrated that a properly used latex condom provides a high
degree of protection against a variety of sexually transmitted
diseases, including HIV infection.
Condoms are classified as medical devices and are regulated by
the Food and Drug Administration. Each latex condom
manufactured in the United States is tested for defects,
including holes, before it is packaged, and several studies
clearly show that condom breakage rates in this country are
less than 2 percent. Even when condoms do break, one study
showed that more than half of such breaks occurred prior to
ejaculation.
Latex condoms can provide up to 98-99 percent protection
against pregnancy and most sexually transmitted diseases,
including HIV infection, but only if they are used
consistently and correctly.
For more detailed information about condoms, see CDC's fact
sheet, "The Role of Condoms in Preventing HIV Infection and
Other Sexually Transmitted Diseases."
The Public Health Service Response
The U.S. Public Health Service is committed to providing the
scientific community and the public with accurate and
objective information about HIV infection and AIDS. It is
vital that clear information on HIV infection and AIDS be
readily available to help prevent further transmission of the
virus and to allay fears and prejudices caused by
misinformation. In addition to research on
the virus and its transmission, the PHS program to prevent the
spread of HIV/AIDS includes counseling, testing, and
education. Through these programs, individuals who have
engaged in high-risk behaviors can receive voluntary
HIV-antibody testing for themselves and their partners, and
those found to be infected can be counseled
regarding preventive services and treatment options, as well
as how to prevent transmission to others.
For more information:
CDC National AIDS Hotline: 1-800-342-AIDS
Spanish: 1-800-344-7432
Deaf: 1-800-243-7889
CDC National AIDS Clearinghouse
P.O. Box 6003
Rockville, MD 20849-6003
CDC National AIDS Hotline Training Bulletin #79
Centers for Disease Control and Prevention
Statement Concerning HIV Transmission
December 21, 1993
This is a statement from the Centers for Disease Control and
Prevention (CDC) concerning the human immunodeficiency virus
and its transmission.
Research has revealed a great deal of valuable medical,
scientific, and public health information about the human
immunodeficiency virus (HIV) and acquired immunodeficiency
syndrome (AIDS). The ways in which HIV can be transmitted
have been clearly identified. Unfortunately, some widely
dispersed information does not reflect the conclusions of
scientific findings. The Centers for Disease Control and
Prevention (CDC) provides the following information to help
correct a few commonly held misperceptions about HIV.
Transmission
HIV is spread by sexual contact with an infected person, by
needle-sharing among injecting drug users, or, less commonly
(and now very rarely in countries where blood is screened for
HIV antibodies), through transfusions of infected blood or
blood clotting factors. Babies born to HIV-infected women may
become infected before or during birth, or through
breast-feeding after birth.
In the health-care setting, workers have been infected with
HIV after being stuck with needles containing HIV-infected
blood or, less frequently, after infected blood gets into the
worker's bloodstream through an open cut or splashes into a
mucous membrane (e.g., eyes or inside of the nose). There has
been only one demonstrated instance of patients being infected
by a health-care worker; this involved HIV transmission from
an infected dentist to six patients. Investigations have been
completed involving more than 22,000 patients of 63
HIV-infected doctors and dentists, and no other cases of this
type of transmission have been identified. Some people fear
that HIV might be transmitted in other ways; however, no
scientific evidence to support any of these fears has been
found. If HIV were being transmitted through other routes
(for example, through air or insects), the pattern of reported
AIDS cases would be much different from what has been
observed, and cases would be occurring much more frequently in
persons who report no identified risk for infection. All
reported cases suggesting new or potentially unknown routes of
transmission are promptly and thoroughly investigated by state
and local health departments with the assistance, guidance,
and laboratory support from CDC; no additional routes of
transmission have been recorded, despite a national sentinel
system designed to detect just such an occurrence.
The following paragraphs specifically address some of the more
common misperceptions about HIV transmission.
HIV in the Environment
Scientists and medical authorities agree that HIV does not
survive well in the environment, making the possibility of
environmental transmission remote. HIV is found in varying
concentrations or amounts in blood, semen, vaginal fluid,
breast milk, saliva, and tears. (See page 3, Saliva, Tears,
and Sweat.) In order to obtain data on the survival of HIV,
laboratory studies have required the use of artificially high
concentrations of laboratory-grown virus. Although these
unnatural concentrations of HIV can be kept alive under
precisely controlled and limited laboratory conditions, CDC
studies have shown that drying of even these high
concentrations of HIV reduces the number of infectious viruses
by 90 to 99 percent within several hours. Since the HIV
concentrations used in laboratory studies are much higher than
those actually found in blood or other specimens, drying of
HIV-infected human blood or other body fluids reduces the
theoretical risk of environmental transmission to that which
has been observed -- essentially zero. Incorrect
interpretation of conclusions drawn from laboratory studies
have alarmed people unnecessarily. Results from laboratory
studies should not be used to determine specific personal risk
of infection because 1) the amount of virus studied is not
found in human specimens or anyplace else in nature, and 2) no
one has been identified as infected with HIV due to contact
with an environmental surface. Additionally, since HIV is
unable to reproduce outside its living host (unlike many
bacteria or fungi, which may do so under suitable conditions),
except under laboratory conditions, it does not spread or
maintain infectiousness outside its host.
Households and Other Settings
Although HIV has been transmitted between family members in a
household setting, this type of transmission is very rare.
These transmissions are believed to have resulted from contact
between skin or mucous membranes and infected blood. To
prevent even such rare occurrences, precautions, as described
in previously published guidelines, should be taken in all
settings -- including the home -- to prevent exposures to the
blood of persons who are HIV infected, at risk for HIV
infection, or whose infection and risk status are unknown.
For example, hands and other parts of the body should be
washed immediately after contact with blood, and surfaces
soiled with blood should be disinfected appropriately.
Practices that increase the likelihood of blood contact, such
as sharing of razors and toothbrushes, should be avoided.
Needles and other sharp instruments should be used only when
medically necessary and handled according to recommendations
for health-care settings.
There is no known risk of HIV transmission to co-workers,
clients, or consumers from contact in industries such as food
service establishments (see information on survival of HIV in
the environment). Food service workers known to be infected
with HIV need not be restricted from work unless they have
other infections or illnesses (such as diarrhea or hepatitis
A) for which any food service worker, regardless of HIV
infection status, should be restricted. The Public Health
Service recommends that all food service workers follow
recommended standards and practices of good personal hygiene
and food sanitation.
In 1985, CDC issued routine precautions that all personal
service workers (e.g., hairdressers, barbers, cosmetologists,
massage therapists) should follow, even though there is no
evidence of transmission from a personal service worker to a
client or vice versa. Instruments that are intended to
penetrate the skin (e.g., tattooing and acupuncture needles,
ear piercing devices) should be used once and disposed of or
thoroughly cleaned and sterilized after each use using
procedures recommended for use in health-care institutions.
Instruments not intended to penetrate the skin but which may
become contaminated with blood (e.g., razors) should be used
for only one client and disposed of or thoroughly cleaned and
disinfected after each use.
Kissing
Casual contact through closed-mouth or "social" kissing is not
a risk for transmission of HIV. Because of the theoretical
potential for contact with blood during "French" or
open-mouthed kissing, CDC recommends against engaging in this
activity with an infected person. However, no case of AIDS
reported to CDC can be attributed to transmission through any
kind of kissing.
Saliva, Tears, and Sweat
HIV has been found in saliva and tears in only minute
quantities from some AIDS patients. It is important to
understand that finding a small amount of HIV in a body fluid
does not necessarily mean that HIV can be transmitted by that
body fluid. HIV has not been recovered from the sweat of
HIV-infected persons. Contact with saliva, tears, or sweat
has never been shown to result in transmission of HIV.
Insects
From the onset of the HIV epidemic, there has been concern
about transmission of the virus by biting and blood-sucking
insects. However, studies conducted by researchers at CDC and
elsewhere have shown no evidence of HIV transmission through
insects -- even in areas where there are many cases of AIDS
and large populations of insects such as mosquitoes. Lack of
such outbreaks, despite intense efforts to detect them,
supports the conclusion that HIV is not transmitted by
insects.
The results of experiments and observations of insect biting
behavior indicate that when an insect bites a person, it does
not inject its own or a previous victim's blood into the new
victim. Rather, it injects saliva. Such diseases as yellow
fever and malaria are transmitted through the saliva of
specific species of mosquitoes. However, HIV lives for only
a short time inside an insect and, unlike organisms that are
transmitted via insect bites, HIV does not reproduce (and,
therefore, cannot survive) in insects. Thus, even if the virus
enters a mosquito or another sucking or biting insect, the
insect does not become infected and cannot transmit HIV to the
next human it feeds on or bites.
There is also no reason to fear that a biting or blood-sucking
insect, such as a mosquito, could transmit HIV from one person
to another through HIV-infected blood left on its mouth parts.
Two factors combine to make infection by this route extremely
unlikely -- first, infected people do not have constant, high
levels of HIV in their bloodstreams and, second, insect mouth
parts do not retain large amounts of blood on their surfaces.
Further, scientists who study insects have determined that
biting insects normally do not travel from one person to the
next immediately after ingesting blood.
Effectiveness of Condoms
The proper and consistent use of latex condoms when engaging
in sexual intercourse -- vaginal, anal, or oral -- can greatly
reduce a person's risk of acquiring or transmitting sexually
transmitted diseases, including HIV infection.
Under laboratory conditions, viruses occasionally have been
shown to pass through natural membrane ("skin" or lambskin)
condoms, which contain natural pores and are therefore not
recommended for disease prevention. On the other hand,
laboratory studies have consistently demonstrated that latex
condoms provide a highly effective mechanical barrier to HIV.
In order for condoms to provide maximum protection, they must
be used consistently (every time) and correctly. Incorrect
use contributes to the possibility that the condom could leak
or break. Proper use should include the following:
* Put on the condom as soon as erection occurs and before
any sexual contact (vaginal, anal, or oral).
* Leave space at the tip of the condom.
* Use only water-based lubricants. (Oil-based lubricants
can weaken the condom.)
* Hold the condom firmly to keep it from slipping off and
withdraw from the partner immediately after
ejaculation.
When condoms are used reliably, they have been shown to
prevent pregnancy up to 98 percent of the time among couples
using them as their only method of contraception. Similarly,
numerous studies among sexually active people have
demonstrated that a properly used latex condom provides a high
degree of protection against a variety of sexually transmitted
diseases, including HIV infection.
Condoms are classified as medical devices and are regulated by
the Food and Drug Administration. Condom manufacturers in the
United States test each latex condom for defects, including
holes, before it is packaged. Several studies of actual
condom usage clearly show that condom breakage rates in this
country are less than 2 percent. Even when condoms do break,
one study showed that more than half of such breaks occurred
prior to ejaculation.
Latex condoms can provide a high degree of protection against
pregnancy and most sexually transmitted diseases, including
HIV infection, but only if they are used consistently and
correctly.
For more detailed information about condoms, see CDC's fact
sheet, "The Role of Condoms in Preventing HIV Infection and
Other Sexually Transmitted Diseases."
The Public Health Service Response
The U.S. Public Health Service is committed to providing the
scientific community and the public with accurate and
objective information about HIV infection and AIDS. It is
vital that clear information on HIV infection and AIDS be
readily available to help prevent further transmission of the
virus and to allay fears and prejudices caused by
misinformation. In addition to research on the virus and its
transmission, the PHS program to prevent the spread of
HIV/AIDS includes counseling, testing, and education.
Through these programs, individuals who have engaged in
high-risk behaviors can receive voluntary HIV-antibody testing
for themselves and their partners, and those found to be
infected can be counseled regarding preventive services and
treatment options, as well as how to prevent transmission to
others.
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