For the last 18 months, the original COVID-19 vaccines — first as a two-dose series, then as boosters — have done an extraordinary job shielding us from illness, hospitalization and death. Globally, they saved an estimated 20 million lives in 2021 alone. Even today, unvaccinated Americans are twice as likely as vaccinated Americans to test positive for COVID — and six times as likely to die from the disease.
But viruses evolve, and vaccines should too.
That was the big-picture takeaway from a pivotal meeting this week of the U.S. Food and Drug Administration’s expert advisory panel. The question before them was simple: Ahead of an expected winter surge, should vaccine manufacturers tweak their forthcoming booster shots to target Omicron — the ultra-infectious variant that has spent the last seven months surging throughout the world in one form or another — or should they stick with the tried-and-true 2020 recipe?
The panel voted 19-2 on Tuesday in favor of Omicron boosters. The question now, however, is which version of Omicron the next round of shots should target.
For anyone who hasn’t been paying attention, the Omicron strain that triggered last winter’s massive COVID wave (BA.1) is now extinct. In March, it was supplanted by the even more transmissible BA.2 … which was supplanted in May by the even more transmissible BA.2.12.1 … which is now being supplanted by the (you guessed it) even more transmissible BA.4 and BA.5.
Experts say BA.5 is the one to worry about: “The worst version of the virus that we’ve seen,” as Dr. Eric Topol, the founder of Scripps Research Translational Institute, recently put it. Together, the closely related BA.4 and BA.5 now account for the majority of new U.S. COVID cases, according to the latest data from the Centers for Disease Control and Prevention — but BA.5 (36.6%) is spreading a lot faster than BA.4 (15.7%). By early July, it will be the dominant strain in the U.S.
That’s troublesome for several reasons. To our immune system, the distance from BA.1 to heavily mutated BA.4 and BA.5 is “far greater,” Topol writes, than the distance from the original BA.1 virus to previous blockbuster variants such as Alpha and Delta — which makes them harder to recognize and respond to. According to the latest research, that could mean:
None of this will set the U.S. back to square one. Despite elevated case levels, there are now fewer U.S. COVID patients in intensive care units than there were during previous phases of the pandemic, and the national death rate (about 300-400 per day) is near the all-time low. Acquired immunity, multiple rounds of vaccination and improved treatment options are helping — a lot.
But combined with waning vaccine protection and disappointing booster uptake among the elderly, the virus’s accelerating evolution and aggressive new trajectory — toward greater transmissibility, evasiveness and possibly pathogenicity — could cause significant reinfections and disruptions if not addressed.
It could also endanger vulnerable Americans in the months ahead.
In late April, BA.5 hit Portugal; by June, more Portuguese people were dying of COVID each day than during the country’s winter Omicron peak. To be sure, Portugal has a larger senior population (23%) than the U.S. (16%), but not by much. And the vaccination rate there is 87%, compared to just 67% in America. Portugal’s booster rate, meanwhile, is nearly twice as high as ours. Infection and hospitalization rates are now rising across much of the rest of Europe as well.
At Tuesday’s FDA advisory meeting, Justin Lessler, an epidemiologist at the University of North Carolina at Chapel Hill, presented a series of projections about how the virus…
Read More: ‘The worst version’ of COVID is spreading. Can we update our vaccines in time?