Covid Omicron Variants and Reinfections

It seems like everyone is getting Covid these days, but not many are really sick or hospitalized. There’s a reason for this – Covid Omicron variants. Should we be worried?

Jeremy Kamil, M.D. is a virologist who answers this question in an article published recently in The New York Times.He says the most recent infections are largely due to the BA.5 Omicron variant. It is the latest of several Omicron variants that have emerged since early 2022. It is more transmissible than earlier Omicron variants, most likely because it’s better at evading our existing antibodies.

BA.5 and its close cousin BA.4 have a key mutation that enables them to sneak past an important class of so-called broadly neutralizing antibodies. These particular antibodies did a great job of preventing infections from a wide swath of earlier Covid variants. But there have been changes. As most of us have observed, many of our vaccinated friends and family members have been infected with the coronavirus for the first time. Some have even been reinfected shortly after their first bout with Covid.

Reinfection a few weeks after recovery is rare, but it happens, depending upon the immune system of the individual. Scientific studies have shown that people who previously contracted Covid-19 are much less likely to get infected with the variant of the day than people who had never seen the virus, and this trend holds true for Omicron. Research from Qatar has shown those who were infected with BA.1 Omicron were significantly less likely to experience BA.4 or BA.5 breakthrough infection months later.

Some studies have found that Omicron variants may induce weaker antibody response than earlier variants, but this is most likely because Omicron causes less severe disease, thanks to immunity from vaccines and prior infections. Immune response is usually proportional to the immune challenge – greater challenge, greater response. This is true for Covid, as well as other infections such as influenza. Vaccines are a great way around this problem; they stimulate our immune systems to make antibodies, without the need for being infected.

This current situation may produce anxiety when we see people getting infected despite being vaccinated, or having been infected with Covid. But despite Omicron’s knack for circumventing antibodies, it’s clear that prior immunity, from either vaccines or previous infections, still protects us from severe outcomes such as hospitalization or even death. There has yet to be a variant that negates the benefits of vaccines. Furthermore, there is no debate that prior immunity reduces the severity of subsequent infections. What’s more, catching the coronavirus more than once or after vaccination does not necessarily put one at risk for the most serious and chronically debilitating forms of long Covid.

Dr. Kamil recommends the FDA move swiftly to authorize new booster shots that target Omicron variants. Existing data suggest that updated shots, even based on earlier Omicron lineages, would be more effective at preventing infections than continuing to use the current vaccine boosters, which are based on the original 2019 coronavirus spike protein.

We all know that the influenza vaccine is updated every year to allow for mutations in the influenza virus. The same is true of the Covid virus. We need, and should expect, annual updates in the Covid vaccine to keep our immune systems protected from Covid virus mutations.

Dr. Kamil summarizes: “Most immunologists I know are cautiously optimistic about our long-term prospects. We don’t know exactly what this virus will do next, and we should never be dismissive of those who have a high-risk profile or are dealing with long Covid. Nonetheless, most of us can have faith in our immune systems, especially when we make use of vaccines and boosters. Recorded history may hold little precedent for the ongoing Covid-19 pandemic. But this is not our immune systems’ first rodeo.”

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