After a person contracts HIV, their immune system begins to develop HIV antibodies. Seroconversion is the period during which these antibodies first become detectable.
Most HIV tests check for the presence of HIV antibodies. So, if a person who has contracted the virus takes a test before seroconversion begins, the result will usually be negative.
During seroconversion, a person may also experience flu-like symptoms, such as a fever and body aches.
In this article, we discuss seroconversion and how it affects testing for HIV.
The length of time between first contracting HIV and developing detectable antibodies can vary because everyone's immune system is different. It can also depend on the type of HIV test that a person takes.
Most HIV tests detect the presence of HIV antibodies.
People usually develop detectable antibodies within 3–12 weeks of contracting HIV.
A person can transmit HIV before seroconversion. Even when the immune system has not yet produced detectable amounts of HIV antibodies, the virus is still active.
In the time between contracting the virus and seroconversion, most people do not know that they have HIV. If they take a test, their result will likely be negative.
Anyone concerned about HIV exposure should speak to a healthcare provider.
When the body is first producing detectable levels of HIV antibodies, people often experience symptoms similar to those of the flu or other viral infections.
Symptoms of seroconversion may include:
These symptoms can also appear during the earliest stage of HIV infection, which is called the acute stage.
The symptoms occur because the immune system is mounting an attack against the virus.
Symptoms usually last for around 14 days, but they can last for months. Some people experience no symptoms during the initial stage of infection.
HIV testing is crucial because it can lead to earlier detection and treatment and less risk of transmission.
The only way for someone to know for sure whether they have HIV is to take a test. Some people may not be aware that they have contracted the virus, because HIV infections do not always produce symptoms.
Authors of a 2016 study concluded that expanding screening criteria to include a broader range of signs and symptoms, such as those listed above, may increase the amount of acute HIV infection diagnoses, which will ultimately advance prevention and treatment strategies.
The Centers for Disease Control and Prevention (CDC) recommend that everyone between the ages of 13 and 64 years old take at least one HIV test, as a routine part of their medical care. The CDC suggest that people with a higher risk of contracting HIV take an annual test.
The accuracy of HIV tests has improved significantly since scientists first identified the virus. However, no test can accurately detect HIV immediately after a person contracts the virus.
There are three main types of HIV test:
Nucleic acid tests (NATs)
These check the blood for the presence of the virus' RNA. They can also determine how much of the virus is present, which is called the viral load.
NATs are accurate during the early stages of infection, but they are very expensive.
Healthcare providers typically reserve these tests for people who have had recent high-risk exposure and who have early symptoms of HIV infection.
Antibody and antigen tests
These test for HIV antibodies and antigens. Antigens are proteins that trigger the body's immune response. HIV produces an antigen called p24, which is present before the body starts producing HIV antibodies.
These tests are now common in the United States.
These test for the presence of HIV antibodies and require a person to give a blood or oral fluid sample. This type includes most rapid, at-home HIV tests.
Antibody tests that use blood from a vein can detect HIV earlier than those that use oral fluid or blood from a finger prick.
In 2012, the U.S. Food and Drug Administration (FDA) approved the OraQuick In-Home HIV Test.
This test kit detects antibodies and requires a sample of oral fluid, which a person collects by swabbing the inside of their mouth. People can take the test at home, and it provides a result in 20–40 minutes.
Other at-home kits require a person to prick their finger and send a small blood sample to a licensed laboratory for testing. These tests are anonymous, and the providers keep information and results strictly confidential.
If the result of any HIV test is positive, the person should take a different test to confirm the results. A healthcare provider can advise about the best follow-up test to take.
Pre-exposure prophylaxis, or PrEP, is a daily medication that people with a very high risk of contracting HIV can take to reduce their risk.
PrEP can significantly lower the risk of infection, but it alone cannot entirely protect people from contracting the virus.
If someone tests positive for HIV, they should stop taking PrEP immediately. Continuing PrEP in this circumstance can cause the virus to become resistant to the treatment.
It is important for people who test positive for HIV to inform any current or former sexual partners. They should also discuss treatment options with their healthcare provider.
One study investigated the benefits of earlier antiretroviral treatment in 4,685 people with HIV.
The researchers found that the participants who had received immediate antiretroviral therapy had a reduced viral load and lower risk of serious health complications, compared to participants who received treatment later, when they had lower CD4+ T cell counts.
CD4+ T cells are a type of white blood cell that fights infection. HIV kills these cells, reducing the immune system's function. A CD4+ cell count is a measure of how healthy a person's immune system is.
Because of the interval between contracting HIV and the start of seroconversion, a negative test result does not necessarily mean that a person does not have the virus.
Anyone concerned about a recent potential exposure to HIV should have a follow-up test after the interval is over. The test provider can advise about the best time to take a second test.
Although there is no cure, treatment can help most people with HIV live long, healthy lives.
This treatment, known as antiretroviral therapy, typically involves taking a daily combination of three or more medications. The medicines reduce a person's viral load to very low levels, slowing the progression of HIV and helping to protect the immune system.
Taking antiretroviral therapy as the doctor instructs can reduce the viral load until it is undetectable. A person with an undetectable viral load has effectively no risk of sexually transmitting HIV to another person.
However, there is not enough data to determine whether a person can still transmit the virus by sharing needles. In addition, experts currently recommend that mothers with HIV do not breastfeed.
Seroconversion is the period during which the body starts producing detectable levels of HIV antibodies. This usually occurs several weeks after initially contracting the virus.
During seroconversion, a person may experience flu-like symptoms, such as fever and body aches.
Anyone concerned about HIV exposure should consider taking a test. If the result is positive, the person will need to take a follow-up test for confirmation.
If the result is negative, an individual may wish to schedule another HIV test, in case they had the first before seroconversion took place.
Although there is no cure for HIV, effective treatments can help most people with the virus to live long, healthy lives.