How long is the AIDS window period stipulated by the state?

At present, China stipulates that the HIV window period is within two weeks.

After three months, the anti-AIDS antibody test is negative, which can completely rule out the possibility of contracting AIDS.

The window period is related to the sensitivity of detection. It used to be six months Due to the lack of sensitivity, the window period is shortened with the increase of the sensitivity of the detection method.

Extended data:

Wang Chen, deputy director of the Department of Science, Technology and Education of the National Health and Family Planning Commission, revealed at the press conference on the 7th that shortening the window period of HIV testing in China from the previous 3 to 4 weeks to less than 2 weeks will effectively reduce the possibility of HIV transmission without antibodies during the window period.

Wang Chen said that at present, China can reduce the new infection rate by 67% by implementing early antiviral treatment for HIV-infected people; The research of comprehensive therapy makes it possible to cure AIDS functionally. Some innovations in the prevention and treatment of second-line AIDS drugs are progressing smoothly, and a number of innovative drugs have entered clinical research.

At the same time, in the prevention and control of other major acute infectious diseases, China has initially established an internationally advanced pathogen tissue screening technology system, and some national institutions have the ability to preliminarily identify 3,000 pathogens within 80 hours.

In addition, China's innovative R&D capability in medical science and technology has been continuously enhanced: the total inventory of national compound samples has reached 1.73 million, ranking first in Asia, and the National Influenza Center has become the only WHO influenza reference laboratory in developing countries.

When it comes to HIV-related substances that can be detected, HIV detection technology and various related HIV detection reagents are naturally inseparable.

At present, common HIV detection technologies include not only HIV antibody detection, but also HIVP24 antigen detection and HIV nucleic acid detection.

Detection reagents are more diverse, not only for blood (serum or plasma), but also for saliva and urine HIV rapid self-test reagents (due to low concentration, it appears later than blood). The mainstream HIV antibody detection reagent has developed to the fourth generation, that is, HIV antibody /P24 antigen combined detection reagent.

For the vast majority of people, a positive reaction will appear when using the third-generation HIV antibody detection reagent 3 weeks after HIV infection 12 weeks, that is, the window period is generally about 3 weeks.

With the emergence and continuous improvement of the fourth generation reagent, the joint detection of HIV antibody and HIVP24 antigen has been realized, and the window period can be shortened to about 2 weeks (2-6 weeks).

However, if HIV nucleic acid detection is applied, the window period can be shortened to about 1 week (1 to 4 weeks).

However, the cost of HIV nucleic acid detection is high, which requires special experimental equipment and environment, and is generally not used as a screening experiment.

Because it takes time to produce antibodies in the body, the length of time for each person to produce these antibodies varies from person to person. This is mainly related to the nature of the immune system inherited by our ancestors.

Therefore, the medical community uses statistical methods to calculate the standard deviation of the time when a large number of people are detected to have antibodies, and then multiplies the standard deviation by three according to statistical principles, thus obtaining the maximum time for an infected person to have antibodies-three months.

In other words, the vast majority of people infected with HIV (99.999%) will not be more than three months without producing corresponding antibodies in their bodies.

So if it is more than three months, if there is no HIV-related antibody in the body, there is a 99.999% possibility of excluding HIV infection.

Statistics focuses on the probability of the future development of events, that is, the size of the possibility. As we all know, the probability of randomly throwing a coin upside down is 50%. If you really throw it ten times or thousands of times, you will find that this 50% does not represent it. Because in reality there will be a possibility of 49% or 5 1%.

The above statistics are also based on the principle of standard deviation, because the calculated value of standard deviation will be infinite acyclic decimal, and the standard difference will be distributed between 25 days and 35 days due to different statistical areas, different samples and different ages.

Because it is inconvenient to use and remember acyclic decimals, they are generally rounded to 30 days, which is equivalent to one month.

According to the statistical normal curve model, between one standard deviation and two standard deviations (that is, between one month and two months), the number of people infected with HIV will account for 67%, 95% between two months and three months, and 99.999% above three months.

Therefore, it can be understood that if the infected person still does not produce relevant antibodies after more than 90 days, the probability is only one in a thousand, that is, one in a thousand infected people still does not produce antibodies after more than 90 days.

For the value of 90 days, the influence of the difference of several days on the probability value of 99.999% can be ignored. The probability of one thousandth of an event can be considered as a small probability event statistically.

Generally speaking, it is a screening method to detect whether there is HIV infection by detecting related antibodies.

So there is no so-called window period. However, this method is more likely to produce false positive results, and it must be done twice in a row, and both results are positive before the test report can be issued.

Health News Network-How to Determine the HIV Window Period

Health News Network-China AIDS testing window shortened to less than 2 weeks.

Baidu encyclopedia-window period of AIDS infection