COVID vaccine gets upgrade; should you get new booster?

We’re overdue; human studies not done

The COVID vaccine is getting an upgrade.

For two years, we’ve been protecting ourselves with a vaccine modeled after the original version of the virus. But soon after Labor Day, a new booster — call it vaccine 2.0 — will be available to every adult in the U.S.

The current vaccine still prevents severe disease and hospitalization, scientists say, but its power is declining. There’s concern that this could worsen the pandemic this fall and winter

ecause the virus has been mutating, “we’re long overdue,” according to Dr. Eric Topol, founder and director of the Scripps Research Translational Institute in San Diego. “The FDA should be commended for wanting to take an aggressive, expedient approach.”

But there are some uncertainties about this updated vaccine’s effectiveness. While the new booster is proven safe, studies about efficacy, so far, have only been completed in mice.

Should you hurry to get it? Here are some thing you might want to consider before deciding.

Q How is it different?

A The new mRNA vaccine product, made by both Pfizer and Moderna, is a two-in- one, or “bivalent” vaccine.

One part targets the spike protein on the original Wuhan strain of the virus, just like the original vaccine. But it also has a second part, which targets a newer mutated form of the spike protein, found in the BA.4 and BA.5 variants that are circulating today. These variants have proven better able to dodge our immune protection.

Bivalent vaccines aren’t a new concept. Vaccines for other diseases are also aimed at both ancestral and mutated strains of a pathogen. For instance, the flu vaccine is designed to protect against four different influenza viruses. The HPV vaccine targets nine strains of the papillomavirus. The pneumococcal vaccine targets 23 different strains of Streptococcus bacteria.

Q When will it be available?

A This past Monday, Pfizer and Moderna submitted their data to the FDA for emergency use authorization. The next day, the Biden administration said it plans to roll out the vaccine in September.

Although the exact timing has not been announced, a panel of the U.S. Centers for Disease Control will discuss the rollout next Thursday and Friday. Then things will move quickly: CDC director Dr. Rochelle Walensky typically adopts the panel’s recommendation within hours, followed shortly by a Western states advisory group and California’s health officials.

If things go as expected, the shot could be ready soon after Labor Day.

Q Should you get it?

A In general, if you have not received a vaccine or recovered from a COVID infection within the past six months, getting a booster is a good idea, say experts.

Your immune response to a shot begins to wane after two months, although some protection persists four to five months later. So think … since February.

“It’s going to be really important that people this fall and winter get the new shot. It’s designed for the virus that’s out there,” Dr. Ashish Jha, the White House’s COVID response coordinator, said at a virtual event hosted by the U.S. Chamber of Commerce Foundation last week.

Q Who is eligible?

A According to the CDC, only people who have already completed their two “primary series” COVID shots will be eligible for the new bivalent booster.

If you haven’t yet gotten the original booster, you can get this new one.

Pfizer’s bivalent booster is designed for adolescents and anyone 12 and older, while Moderna’s is for adults 18 and older.

Q You’re vaccinated and boosted, but got COVID a month ago. Should you still get the new booster?

A Eventually, yes. But not right now.

“Wait. The immune system was just ‘super boosted’ with the infection and it’s still processing & ‘learning,’ ” tweeted immunologist Dr. Michael Mina, formerly of Harvard’s School of Public Health and now at eMed.

Q Why is this booster being rolled out, if it hasn’t yet been proven effective in people?

A The FDA says the shots are safe and will prove to help fend off disease. “How confident am I?” Dr. Peter Marks, the FDA’s top vaccine regulator, said in an interview with the New York Times. “I’m extremely confident.”

In preclinical data presented by both Pfizer and Moderna to the FDA in June, the bivalent vaccine design seemed to perform better than the single-target vaccine.

In eight mice, Pfizer’s bivalent booster generated a 2.6-fold increase in neutralizing antibody levels against the BA.4 and BA. 5 subvariants, compared with the companies’ current booster. Lab work by Moderna showed its new booster increased neutralizing antibodies against the new variants 8-fold, while the original booster only increased antibody levels around 4.4-fold.

The companies are now conducting clinical studies in humans. But those results probably won’t be ready until late October or early November.

Q Is the urgency to roll out the new vaccine a first?

A There’s precedent for this approach. The annual flu vaccine program, for example, is updated using only mouse data.

Some scientists, such as Topol and Dr. Paul Offit of the University of Pennsylvania, say that’s not good enough. They say the new COVID booster may not work as well as the mouse data suggests — and want proof that it offers significant clinical improvement over the current booster.

“We’ll know much more about the bivalent booster in the weeks after the program is launched,” said Topol. While people are quite likely to benefit from the new booster, he said, “I will wait to see some data before getting it. Maybe I’m a bit too conservative, maybe too datadriven for my own good.”

But others say there’s enough experience with the previous vaccines to be confident that the shot is safe. The antibody data suggests that it works, they add. And they worry about growing risks of illness this winter.

Dr. Bob Wachter, who chairs the department of medicine at UC San Francisco, isn’t waiting.

“I’ll take mine as soon as I’m eligible,” he tweeted.