What we know about SARS-CoV-2, the virus causing COVID, is that it is here to stay. Information is continuing to evolve and research is still on going as new discoveries are being made. What we DO know is that COVID-19 is not over yet. It is still prevalent in many cities, states and countries and the United States remains stuck at an uncomfortable high plateau of pandemic pain and misery while new variants are driving a case surge in Europe.
We used to think that once you were infected and recovered from the virus your odds of dying were very low and both prior infection and immunization showed an even more protective effect against severe disease in certain populations. Age, underlying comorbidities and gender were the main risk factors for illness severity and reinfection. That was based on surveillance information from January 2020 through May 2021. Things have clearly changed.
Last year we thought that reinfections were relatively rare. Now we are seeing people infected 2, 3 or even 4 times after being fully vaccinated and boosted! What gives???
We have to remember that the virus strain that’s circulating now is very different then earlier strains. If we have been infected with COVID-19 or vaccinated, our body creates an immune response and mounts antibodies against future infections. It recognizes the strain that our body was originally in contact with. But as the virus changes as it has with Omicron, it becomes a fuzzier picture for our immune system to recognize the virus and we get re-infected. Omicron by far has been the Hercules of all variants in that it continues to shape-shift into other versions of itself making it more difficult for our antibodies, B cells and T cells to recognize and shut down a growing infection before the next subvariant arrives. What this means is that Omicron infection may have boosted our immunity against earlier variants, but it is less effective against itself and its subvariants (B.1.1.529, BA.4, BA.5, BA.1, BA2, BA.3, BA.2.H78Y). This poor immunogenicity against itself explains the resurgence of reinfections.
The BA.5 and BA.4 subvariants of Omicron account for 70% of all infections in the U.S. “It is the worst version of the virus that we’ve seen” according to Eric Topol, professor of molecular medicine at Scripps Research. He states that it takes “immune escape” to the next level which enhances transmissibility beyond earlier versions of Omicron. Fortunately due to the immunity build up from the winter omicron wave, there has not been a significant increase in hospitalizations or deaths. The BA.5 is different in its biology in that it is able to evade the body’s immune system and go unrecognized by our T-cells.
The answers are more than alittle murky. Stay tuned…as we wait for more studies and more clear guidance.
References: http://Variants Dampen Immune Protection