New COVID-19 vaccine boosters that target omicron variants are being distributed following emergency use authorization by the Food and Drug Administration and recommendation by the Centers for Disease Control and Prevention. Microbiology professor Christopher Brooke, a virologist and vaccine expert, discussed with News Bureau biomedical sciences editor Liz Ahlberg Touchstone what makes these boosters different and who should get them.
Why do we need more COVID-19 boosters, especially since the omicron variants seem to be less deadly?
In short, boosters are required to keep up with the rapid evolution of this virus that has been circulating in humans for nearly three years. The viruses that are circulating now have changed a lot since the original virus that emerged in late 2019, which was targeted by the earlier vaccines and boosters. As a result, the vaccines we have been using do not work as well against recent variants like BA.5 as they did against earlier variants.
The omicron variants appear less deadly than earlier variants because so many more people now have some degree of immune protection against the virus – from vaccination, prior infection or both – that they did not have when earlier variants were circulating. Obtaining immune protection through vaccination is much safer than obtaining it from infection.
What makes these shots different from the last round of boosters? They are “bivalent” – what does that mean?
“Bivalent” just means they target two distinct viral strains. For comparison, seasonal flu vaccines are “quadrivalent,” meaning they target four different strains of influenza virus.
The new vaccines now include a sequence for the spike protein of the BA.5 variant, which recently has been the most dominant variant, in addition to the original Wuhan1 spike sequence that has been included in COVID-19 vaccines from the beginning. This means that the new boosters will train your immune system to recognize the viruses that are currently circulating in the community, as well as those older strains that circulated a couple years ago.
Who should get an omicron booster?
Anyone who has had their primary series of COVID-19 vaccines and has not been infected in the last six months should get a new booster. If you have been infected in the past six months, your immune system has already seen omicron and the booster will not be as helpful.
If someone hasn’t gotten the initial COVID-19 vaccine series, can they just jump to the omicron shot?
The original COVID-19 vaccine series is still required prior to getting the updated booster.
Will these be the last COVID-19 boosters or will there be more to come?
This virus is with us for the long term, unfortunately, and we will almost certainly have to get updated boosters from time to time, similar to what is required for flu. It remains to be seen how often updated boosters will be required – it could be yearly, it could be every few years. It depends on how fast the virus keeps evolving.
