Authors: Li Taisheng (Peking Union Medical College Hospital), Cao Wei (Peking Union Medical College Hospital), Song XiaoZ (Peking Union Medical College Hospital), Liu Xinchao (Peking Union Medical College Hospital), Luo Ling (Peking Union Medical College Hospital)
1. Why do you feel that gay men are more likely to be targeted by AIDS?
The reason why gay men are at a high risk of HIV infection is because of their special sexual intercourse – anal sex, and the fact that there are many and variable sexual partners.
Anal sex is more likely to cause the spread of the virus: first, the rectal lining is easily damaged due to the shape and epithelial structure of the rectum, as well as the violent anal sex action, resulting in the spread of the virus; secondly, The alkaline environment in the rectum is suitable for the survival and reproduction of HIV virus.
In addition, in most cases, men who have sex with men often do not have a fixed sexual partner and are often reluctant to use condoms during anal sex, resulting in cross-infection of HIV or other sexually transmitted diseases.
2. Are HIV test strips sold online reliable? How to detect the most accurate?
Using the test strip method for the initial screening of HIV infection is simple and widely used.
Ordinary people can use test strips for self-testing, and many medical institutions also use test strips for primary screening.
Regular AIDS test strips all have production batch numbers that can be queried by the State Food and Drug Administration, with an accuracy rate of more than 95%, which is a relatively “reliable” preliminary screening choice, but not be used as a basis for diagnosis.
If the initial screening of the test strip is positive, it is necessary to go to a regular medical institution as soon as possible to conduct a confirmatory test and other necessary tests to confirm the infection.
It should be noted that the test strip has a definite applicable time, and it must be used after the HIV infection window period (the period from HIV infection to the appearance of detectable antibodies in the human body). Significant.
In most infected people, the window period varies from 2-6 weeks. That is to say, it is meaningless to repeat the dipstick test within 2 weeks after the high-risk behavior occurs.
If the high-risk behavior has not been positive by 3 months, the likelihood of infection is extremely low.
Image source: Zhanku Hailuo
3.Aside from testing, are there any symptoms that can identify HIV infection?
After HIV enters the human body, there will be three stages, namely acute stage, asymptomatic stage and AIDS stage. The clinical manifestations of each stage are different.
First enters the acute infection phase: usually occurs 2 to 4 weeks after the initial infection. Some infected people have symptoms such as fever, sore throat, rash, joint pain, and swollen lymph nodes.
Then enter the asymptomatic period: Usually the infected person has no symptoms during this period.
The last stage of AIDS: manifested as various opportunistic infections and tumors, with various clinical symptoms.
When long-term diarrhea (more than 3 stools per day, >1 month), significant weight loss (more than 10% weight loss within 6 months); repeated oral leukoplakia (Oral Candida infection); recurrent herpes zoster; progressive aggravation of dyspnea; recurrent pneumonia; cerebral infarction or neurocognitive decline in young people; , it is recommended to go to the hospital in time.
4. What is the “window period”? Does it mean that HIV is infected but cannot be detected?
The window period is the period of time after the HIV virus infects the human body until sufficient amounts of antibodies are produced in the blood to be detected by a test method.
During this period, although the human body has been infected with the HIV virus, the indicators of viral infection (p24 antigen and antibodies) in the blood have not yet appeared or are too small to be detected.
Patients in the window period are more contagious. All detection methods have a window period, and the length of the window period is related to the detection method, the type of sample tested (plasma, finger blood, saliva, etc.), and whether pre-exposure or post-exposure drugs have been used.
At present, large hospitals in China have widely used the fourth-generation kits recommended by the British and American guidelines to detect HIV infection, and 75% of infected people can be detected by the fourth-generation kits within 24 days after exposure.
Four-generation kits can detect 99% of HIV-infected individuals within 44 days of exposure.
The “quick test” that can get test results immediately is a second-generation test method with a longer window period, and 75% of infected people can be detected within 37 days after exposure .
99% of HIV-infected individuals can be detected within 57 days of exposure.
The above data are based on plasma testing. If the test sample is blood or saliva, the window period may be several days longer.
If the above test is negative the first time, it should be retested 90 days after exposure to HIV.
5. Is there any “regret medicine” that I can take after a high-risk behavior? Where can I buy it?
In healthy people who are not infected with HIV, post-exposure prophylaxis (PEP) can be used to prevent infection after exposure to HIV by taking antiretroviral drugs.
However, PEP must be started within 72 hours of exposure, the sooner the better, as each hour of medication will be more effective in preventing infection.
PEP is a prescription drug that needs to be taken for 28 consecutive days for it to work. When administered correctly, PEP is effective in preventing HIV, but it is not 100% effective.
If you are unsure of your HIV status and have experienced the following within the last 72 hours, you should consult the infectious disease department of a designated AIDS hospital as soon as possible:
Possible exposure to HIV during sex (eg, anal sex, ruptured condom, etc.);
Sharing needles with others for drug use;
being sexually assaulted.
6. Is “AIDS vaccine” true or a rumor?
Since HIV was first discovered in 1983, the global scientific community has devoted a lot of resources to the research on AIDS vaccines, but so far there has been no major breakthrough. AIDS vaccines are considered to be one of the most difficult vaccines to overcome.
In recent years, clinical trials of HIV vaccines have been significantly accelerated. For example, the trial of the repeat RV144 vaccine in South Africa started in 2016. The Chinese Center for Disease Control and Prevention and the National Institutes of Health (NIH) jointly The DNA-replicative poxvirus (rTV) of the former is developed.
But there is no effective HIV vaccine yet.
Image source: Zhanku Hailuo
7. Is it true that some people are born immune to AIDS?
When HIV virus attacks human immune cells CD4 cells, in addition to identifying CD4 cells, it also needs to recognize the receptors on the surface of CD4 cells.
This receptor is like a door lock for the cell. Once the virus is successfully paired, the HIV virus can smoothly enter the interior of the CD4 cell through this door.
There are mainly two door locks on the surface of CD4 cells, one is called CCR5 and the other is called CXCR4. HIV virus mainly enters the cell by opening the lock of CCR5, but a considerable number of HIV viruses also pass through Turn on CXCR4 into cells.
The immune cells of the vast majority of people in the world have both door locks at the same time, so no matter what kind of “unlock function” of HIV is encountered, the immune cells are powerless.
However, there are a very small number of people, mainly Caucasians, whose cell surface CCR5 structure has changed in evolution, making HIV viruses that specialize in CCR5 fail to recognize and be rejected Outside the door, the phenomenon of “immunity” against AIDS has emerged.
However, after all, there is still CXCR4 locked in, and the natural immunity of AIDS is not absolute.
8. The three transmission channels of AIDS seem to have nothing to do with me. Is there anything I need to pay attention to in my life?
Being able to name three routes of HIV infection shows that you have at least some knowledge about it.
Yes, HIV can only be acquired or transmitted through certain behaviors. HIV is most commonly acquired or transmitted through unsafe sex, sharing needles or syringes.
Remember that only certain bodily fluids, primarily blood, semen, rectal fluid, vaginal fluid, and breast milk, can transmit HIV and that these fluids must come into contact with mucous membranes or damaged tissue, or It can be spread by direct injection into the bloodstream (from a needle or syringe).
Mucous membranes include rectal, vaginal, penile, and oral mucosa.
Actually, clinically, there are three main types of infected persons:
Having unprotected anal or vaginal sex with someone living with HIV without the full use of a condom.
Receptive anal sex is the highest risk sex for HIV-negative partners, but the partner who penetrates the anal can also get HIV.
Any partner can contract HIV through vaginal sex, although the risk is smaller than the risk of receiving sexual anal sex.
Share needles or syringes with someone living with HIV.
Transmission from mother to baby during pregnancy, childbirth, or breastfeeding.
The risk can be high if the mother has HIV and is not on medication, but now we test all pregnant women for HIV and start antiretroviral therapy immediately, which greatly reduces the risk of The risk of a baby being born with HIV.
Saliva, tears, or sweat are safe if they don’t mix with the blood of an HIV-positive person.
hence hugs, handshakes, shared toilets, shared dishes, or courtesy kisses with HIV-positive people and other things that do not involve bodily fluidsExchanged sexual activity (such as touching), none of which can cause HIV transmission.
9. Can AIDS patients get married and have children?
AIDS patients, like ordinary people, have the right to love, marry, and have healthy babies.
In terms of marriage and childbirth, there is no legal prohibition, only one is the obligation to inform partners of infection. With the informed consent of the other party, it is completely possible to get married and have children.
If only one of the spouses is HIV-infected and wants to get pregnant, the safest method is semen processing (sperm elution) and artificial insemination. Or let the positive partner continue to take antiviral drugs to suppress the virus to the greatest extent, and the negative partner takes pre-exposure prophylaxis (PrEP) every day, and does not use condoms during the woman’s ovulation period, which can also prevent HIV from spreading between partners.
For mothers who are HIV-infected themselves, they can be treated according to the diagnosis and treatment standards of mother-to-child blocking. Taking antiviral drugs can reduce the number of viruses in the mother’s body and reduce the risk of children contracting AIDS in utero. probability.
The baby should also take antiviral drugs within 6 hours of birth (the maternal and child health care institutions will provide them free of charge) for one and a half months.
At the same time, breastfeeding or mixed feeding should be avoided, and artificial feeding should be chosen, avoiding the contact of mother’s blood and body fluids with the baby, scientific nursing, and regular physical examination, so as to create a good and healthy growth environment for the baby.
Image source: Zhanku Hailuo
10.Are HIV patients on treatment no longer spreading the virus?
A patient with AIDS receiving effective antiretroviral therapy, if the treatment is successful, will rapidly drop plasma viral levels to a range that cannot be measured by existing tests.
We call it “below the lower limit of detection,” and it’s a sign of successful antiviral therapy. At this time, the infectivity of the patient will be greatly reduced.
A large number of studies have shown that HIV-infected persons who are on stable antiretroviral therapy are less likely to transmit HIV if their plasma viral load remains undetectable for more than six months. The risk is extremely low.
However, that doesn’t mean unprotected sex is okay. Even if AIDS patients have very good medication compliance, 15-25% of patients may have one or several transient increases in plasma viral load after virus control. This increase lasts for a short time and can be spontaneously increased. Relief, but the reason behind the mechanism is not very clear.
Although scientists and doctors currently believe that this phenomenon does not affect the effect of long-term treatment, after all, it is impossible to monitor virus levels in real time, and there is no way to predict when transient virus fluctuations will occur , so sticking to protective measures is still the best option.
Therefore, even in patients with good viral control after antiretroviral therapy, protected sex is still recommended.
*The content of this article is for the popularization of health knowledge. It cannot be used as a specific diagnosis and treatment recommendation, nor can it replace the face-to-face consultation of a licensed physician. It is for reference only.
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