Covid-19 reinfection is possible and should inform pandemic priorities moving forward

A year after the discovery of the SARS-CoV-2 virus, the end of the pandemic seems just over the horizon as more and more hope that a highly effective vaccine may soon be widely available. Returning to a reality without Covid is a desire we all share, but there is reason to believe that we may never be free from Covid again due to the real possibility that Covid-19 will become an endemic disease; once infected people can be reinfected.

We still know little about the incidence of Covid-19 reinfection. There have been official cases on all continents and no doubt many others have not been reported. A Hand the report confirmed that in mid-October the virus reinfected a man in Nevada. His symptoms were more severe during the second infection, but he has since recovered. Whether the symptoms are worse with the first or second infection seems to vary from case to case.

This means that reinfection occurs despite the body’s immune response with the production of antibodies or T cells. Common knowledge suggests that when I am sick, my body mounts an immune response against my specific disease to prevent disease along the way. Street. While this is technically correct, a vigorous immune response, including antiviral antibodies and T cells, does not guarantee lasting protection from disease. While some antibodies last for decades, such as measles, others can last for six months or less. We do not know precisely how long our protective immune response to Covid-19 may last, but the first indications seem to point towards a few months.

This could explain why confirmed cases of reinfection are so rare, as well as why many more reinfections are likely to occur. If the first or second infection is asymptomatic, that infection may not be detected by the host. Of the fifty-five million global infections to date, it seems likely that Covid-19 has reinfected more than five people.

Due to these uncertainties and the importance of reinfection, we call for a significant research effort to investigate this topic. This study would be built by first sequencing the virus from a large cohort of Covid-19 patients when they first present. Then we would track them and check them regularly with rapid antigen tests. These tests are the most efficient way to monitor the most contagious patients: asymptomatic and presymptomatic patients. The use of rapid tests means that most of this study could include asymptomatic and presymptomatic patients, whose sequences could be used for later research.

For each patient who tested negative and then positive, the sequence is rerun to determine one of the two possibilities. Either the virus persisted and re-emerged, or it was a new infection. The true extent of reinfection can only be recognized after two or three years of such studies.

Understanding reinfection is needed to inform the COVID-19 control strategy moving forward. Herd immunity strategists claim the potential to quickly end the pandemic and save the economy (at the expense of millions of deaths). They believe that a population exposed to the virus will trigger a widespread immune response and the development of antibodies and T cells to the point where the virus will no longer spread. Even if our immune responses fail over time and reinfection can occur, herd immunity will fail along with them.

Our understanding of SARS-CoV-2 reinfection will also impact our vaccination strategy. Suppose a double dose of a Covid vaccine only protects for months instead of years. If so, we will have to rethink the costs of manufacturing, distributing, accepting the vaccine for multiple doses, immunization frequency, etc. Studies of New England Journal of Medicine is Science have indicated that naturally produced antibodies can only last for two to five months. Vaccines may not be a silver bullet to stop the virus, but rather one of many tools to collectively tackle the pandemic.

All of this research is preliminary, and we won’t know the full extent of vaccine-based immunity until an approved vaccine has been around for a long time. Maybe the vaccine want be effective enough to expel the virus almost completely. We will have to wait and see, but we need to understand reinfection before we can figure out what is the best strategy to contain Covid, whether it is a vaccine or not. Be optimistic but cautious, because the pandemic is far from over.