Taking stock of Covid Vaccines

Sunday - September 10 2023, 11:52 UTC - 1 year ago

Last week I got a reminder of how uncertain this fall wave of Covid-19 is due to the updates to the vaccines. The US and Europe are expecting three different updated shots from Pfizer, Moderna, and Novavax, and in Europe it has already been approved whereas in the US, the CDC's Advisory Committee on Immunization Practices is set to meet on September 12. FL 1.5.1 and EG.5 are notable variants of concern, with EG.5 being the most common at 20%. Scientists are paying attention to the BA.2.86 variant, known as pirola, which has over 30 mutations in spike.

Last week I came down with some kind of bug. So I got to play one of my least favorite games: "Covid or Not Covid?" In my case, two rapid tests were negative, so probably not covid. But many other people have been testing positive. Covid hospitalizations in the US rose nearly 16% during the third week of August. Even Jill Biden got covid this week. Data suggest we’re at the beginning of a fall wave. And with students returning to schools and workers returning to offices, I’m sure I’m not the only one who is thinking about covid vaccines. It’s been a year since a booster was released, and while the latest wave isn’t likely to be as bad as the tsunami we experienced in 2021-2022, there’s a lot of uncertainty about what the next few months look like. So for this week’s Checkup, let’s take stock of where we’re at. Where are the updated shots? And how do they stack up against the new variants? .

Depending on where you live, as soon as this month. At the beginning of the summer, the US Food and Drug Administration decided that the vaccine needed a refresh. The agency advised manufacturers to develop vaccines targeting XBB.1.5, a descendent of omicron and one of the dominant variants circulating at the time. Pfizer, Moderna, and Novavax have done that. Now they’re waiting on FDA approval, and guidance from the Centers for Disease Control and Prevention on how the shots should be administered. That should all happen by mid-September. The CDC’s Advisory Committee on Immunization Practices, the body that provides guidance on who should get vaccinated and when, is set to meet next week, on September 12.

In Europe, Pfizer’s new vaccine is already approved. The European Commission greenlighted the shot last week. And this week regulators in the United Kingdom followed suit. The first shots should be going into arms soon. Those at greatest risk of developing serious illness in the UK will be eligible for the new shot starting September 11.

XBB variants are still causing the majority of infections in the US, but a couple of other variants have been gaining ground. According to CDC estimates, EG.5 is now responsible for about 20% of covid-19 cases in the US, more than any other single circulating variant. A variant called FL 1.5.1 comes in second, making up 15% of cases. These viruses don’t seem to cause more severe disease, but they are more adept at evading the body’s immune response.

Scientists are also paying close attention to a variant first detected in early August known as BA.2.86 or, by its nickname, pirola. This variant is notable because it’s so unlike any of the other versions circulating. "What really caught people’s attention is that it had over 30 mutations in spike, so a very substantial genetic change," says Dan Barouch, an immunologist at Harvard University, referring to the sharply protruding protein the virus uses to gain entry into cells. It’s only the second time that SARS-CoV2 has made such a big leap. (The first time was the jump from delta to omicron, a shift that led to the deadliest covid wave to date.) The worry is that this massive change in sequence might make the virus harder for our immunities to recognize than the existing vaccines can anticipate, requiring yet another booster.