More than 61 million doses of Covid-19 vaccine have been given in the United States
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Dr Matthew Binnicker, an expert in diagnosing infectious disease, explains the benefits and limitations of a diagnostic test as more people receive Covid-19 vaccines.
More than 61 million doses of Covid-19 vaccine have been given in the United States since December 2020. As more people get the vaccine, this means that the place of other mitigation measures, such as diagnostic testing, starting to change.
Even as the pace of vaccine production and circulation has increased, some experts believe it could be mid to late summer before most Americans get a chance to to be vaccinated. Until then – and possibly for months afterward – measures including shelter and physical speed will be needed to prevent a relapse in Covid-19. A diagnostic test will still be an important tool, but there are some limitations. Here are the answers to some common questions about Covid-19 vaccines and testing.
Could the vaccine test positive for Covid-19?
In the days and weeks after the Covid-19 vaccines became available, healthcare professionals saw that some vaccines were confirmed by rapid PCR and antigen tests (this is an update on the different types of tests). This immediately caused patients and their doctors to question whether the vaccine could pass a positive test.
The two Covid-19 vaccines (Pfizer / BioNTech and Moderna) currently authorized for use in the United States are mRNA-based vaccines. They do not contain the entire genome of the SARS-CoV-2 virus, which causes Covid-19. Instead, these vaccines are made up of a small section of the viral genome, which enters the host cell and “uses” the cell to produce a specific viral protein (ie, the Spike protein). ) from which an immune response is generated. RNA molecules are largely unstable, targeted by an enzyme that can disinfect the RNA within hours. Therefore, mRNA-based vaccines do not test for Covid-19 PCR test. Similarly, these vaccines do not give rapid antigen tests to be positive, since the proteins released after vaccination are not expressed in the respiratory tract (i.e., nasal), sampled for Covid-19 PCR or antigen testing.
So what does it mean when a vaccinated person tests positive? They appear to be infected with SARS-CoV-2 just before or after vaccination. Although conventional Covid-19 vaccines may not completely prevent a person from becoming infected, they appear to reduce the incidence of asymptomatic infection and have shown a high level of efficacy in preventing infection. symbolic and very bad.
Do I need an antibody test after the vaccine to make sure I am immune?
Following the immunization, some may question the success of the vaccine, with an interest in testing to determine their immune status. Some laboratory tests, called serology tests, are designed to detect antibodies that are formed in response to infection. While these tests may provide information as to whether an individual has been exposed to a virus in the past, they may not provide a reliable measure of an individual’s immunity to the virus.
Serology tests for infectious diseases do not usually tell us whether antibodies against a pathogen are present or absent, but they do not provide specific details on “How much”Antibody is present. Thus, a person can test positive for antibodies, but the amount of antibodies detected by the test does not always correlate to the amount needed to protect them from becoming ill. Similarly, a negative antibody test does not always mean that a person is not immune, because another part of the immune system, such as T cells, can play a vital role in fighting infection. Due to these limitations, routine antibody testing is unlikely to be recommended after Covid-19 vaccination.
Do we need to test for Covid-19 after the pandemic has ended?
Cases of Covid-19 are declining in many parts of the world, possibly as a result of a combination of tight measures, potential seasonal effects and increased immunity to natural and immunosuppressive diseases. However, new changes to SARS-CoV-2 indicate that there is significant potential for further increases in Covid-19 cases. Whether or not recovery occurs, at some point, the pandemic will end. When that happens, it’s unclear what will happen to Covid-19.
Will SARS-CoV-2 disappear completely, or will it become an endemic cause of respiratory illness? As SARS-CoV-2 has reached all parts of the world and will continue to circulate over time, it is more likely that Covid-19 will continue to cause an outbreak of moderate to severe respiratory infection. , perhaps with a flu-like seasonal pattern. Therefore, testing for Covid-19 is likely to remain important even after the spread of the pandemic. Healthcare providers need to differentiate between Covid-19, influenza and other causes of respiratory disease in order for patients to be treated and managed effectively. In other words, Covid-19 is very likely to be with us – at least in part – for years to come.
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