Since the beginning of the current pandemic, scientists and doctors have wondered why there is a very low rate of reinfection with the dreaded SARS-CoV-2 virus; the virus that causes COVID-19 infection. They have wondered if this is a result of the production of antibodies by the body’s immune system and therefore, a build-up of immunity and protection against the virus after the first infection. If this is the case, then there is hope for preventing future infections, reinfections, and generally wiping out this disease completely.
A recently published study by the National Cancer Institute (NCI) says that people who were previously infected with SARS-CoV-2 appear to be adequately protected against being reinfected with the virus for a few months.
The research was led by Lynne Penberthy, M.D., M.P.H., the associate director of NCI’s Surveillance Research Programme and the research focused on understanding if the detectable antibodies produced against SARS-CoV-2 in the human body protect the person from future reinfection with the virus, to what extent it provides such protection and for how long the protection could last. The researchers worked closely with health care data analytics companies (HealthVerity and Aetion, Inc.) as well as five commercial laboratories including Quest Diagnostics and Labcorp).
The NCI compiled and analyzed patient information which was obtained from several reliable sources which included commercial laboratories, private insurers, and electronic medical records. The privacy of patient’s health information was protected and relevant patient privacy laws were strictly adhered to.
The antibody test results of over 3 million people who had had a SARS-Cov-2 antibody test between January 1 and August 23, 2020, were collected. Antibody tests are used to detect serum antibodies produced by the body’s immune system in response to a particular or specific foreign or infectious agent and in this case; SARS-CoV-2. 12% of the antibody test results were positive while most of the other results were negative. Only about 1% of the results were inconclusive.
Some of these individuals from the percentage that tested positive and from those who tested negative were further tested using a Nucleic acid amplification test or PCR test to see which percentage will test positive to a PCR test. The results were reviewed at certain intervals ad it was discovered that about 3% of the seronegative individuals tested positive to a PCR test while the rate at which the seropositive individuals tested positive to the PCR test declined over time.
To determine if there are cases of reinfection amongst the people who tested positive to the first antibody test, the researchers analyzed their PCR test results 90 days after and only about 0.3% still had a positive PCR test result.
These results point out that having antibodies against SARS-CoV-2 provides a form of protection from future infection by the virus. This kind of study is relevant because it gives insight into the possibilities of vaccine production and distribution, resumption of normal work, school, and other public activities as well as opens doors for more research on treatment options for COVID-19.
In summary, this study may encourage the school of thought that believes in the production of antibodies against the SARS-CoV-2 virus and the protective effect, however, it sheds little light on the duration of this protection as well as its strength. There is also a need to do more studies to find out how a patient’s co-morbid conditions can affect this protection.