CDC’s Messonnier: We can’t change the Covid-19 vaccine regimen unless we know it works

In an effort to stretch the supply of Covid-19 vaccines, some have advocated for further spacing out the two doses required for some of the shots or, in the case of the Moderna vaccine, lowering the dosage given with each jab.

But Nancy Messonnier, the director of the Centers for Disease Control and Prevention’s National Center for Immunization and Respiratory Diseases, reiterated Tuesday that federal health authorities continue to stand behind the current recommendations about the timing and strength of the shots, which were proven to be protective in clinical trials. She added that regulators and officials would continue to review new data as it was released.

“We have to stick with what we know works,” she told STAT reporter Helen Branswell during a live virtual conversation. “This is the regimen that’s been carefully studied. We’ve promised the American public that we would follow the data and follow the science, and that’s what we’re doing.”


So far, U.S. regulators have authorized three Covid-19 vaccines, a one-shot immunization from Johnson & Johnson and two-dose regimens from Moderna and Pfizer-BioNTech. The interval between Moderna doses is 28 days; for the Pfizer shot, it’s 21 days.

Some lawmakers and scientists have called for extending that period to get more people an initial dose, a step that some other countries have pursued. They’ve also called for looking into giving a lower dosage of the Moderna vaccine, which, as given now, contains about three times as much vaccine as the Pfizer shot. The U.S.’s vaccine development program has asked Moderna to study if the dosage could be reduced without pinching the amount of protection it confers.


But without additional data, Messonnier cautioned against such a move. She questioned whether lowering the dosage might have an effect on how long the vaccine guards people or reduce the quality of protection it provides.

“What folks have to understand is that there’s not just the efficacy today that we’re looking at,” she said. “We also want a vaccine that’s going to offer long duration of protection, because I frankly don’t want to have to do this more often than we need to, in terms of booster doses. We want a vaccine that not only protects the individual, but also protects the individual from transmitting.”

Messonnier also highlighted how, in the coming weeks, the vaccine supply in the country will increase, which will put greater pressure on immunization campaigns to reach people beyond those who are eagerly lining up for their shots. Some people remain hesitant about the vaccines, whereas others — including incarcerated people, people who are homebound, or people who don’t have internet access — will need special outreach to ensure access.

“This campaign has to be local,” she said. “In every local health department, and every local community, we need everybody to identify those populations and help us figure out how to access them.”

Branswell asked about plans to connect with young conservative men, a group that polling indicates are among the least likely to get immunized, but Messonnier answered generally, speaking about the need to reach out to community leaders and influencers no matter the demographic in question. She cited going to a vaccine clinic over the weekend that a pastor from a local Black church helped arrange.

Still, Messonnier acknowledged that health officials should have started their outreach and education efforts earlier last summer, “to really give people the time to grapple with what we were asking them to do in the winter.” She said that public health workers can help expand vaccine coverage by listening to people’s questions and by providing honest, forthright answers that specifically address how the questions were asked.

Messonnier, who has been vaccinated, described getting the shots as “an empowering choice” and that it was her goal to help people understand what a vaccine could do for them in terms of protecting them from Covid-19, but also protecting their families and communities.

“It’s an incredible feeling of relief to feel like, after such a long year and such a long winter, you actually have that measure of protection yourself,” she said. “I really hope everyone will understand that and want to feel that way.”

Source: STAT