Fauci Warns Against Delaying Second Shots as Biden Looks to Ramp Up Initial Jabs Amid Supply Concerns

Anthony Fauci, the leading U.S. authority on infectious diseases, has cautioned against putting off second doses of Pfizer/BioNTech’s and Moderna’s vaccines to accelerate initial vaccinations, a strategy the UK is currently using and one President Biden has said he will adopt as vaccine makers experience delays in vaccine shipments.

“I would be concerned about that because you don’t get full efficacy until you get that second dose,” Fauci said in an interview. “If you allow suboptimal efficacy you could actually immunologically select more for mutations when you do that. It may not be the case, but it gets risky, and that’s the reason why we’d prefer to keep it on the time that the clinical trials said [for Moderna and Pfizer].”

Biden has vowed to immediately release supplies of shots without reserving stocks of second doses meant to ensure patients get fully vaccinated on time (DID, Jan. 19). The U.S. faced criticism under the previous administration for a slow rollout of vaccines that didn’t come close to hitting then-President Trump’s target of having 20 million Americans vaccinated by the end of 2020. Biden has set a goal of administering 100 million shots in his first 100 days as president.

UK Health Secretary Matt Hancock has defended the UK’s use of the strategy, claiming that initially vaccinating as many people as possible is critical with vaccine supplies currently so constrained. Though some experts contend that vaccines should strictly be given according to the regimens proven effective in late-stage trials, Hancock said that first doses likely still provide a good enough level of immunity to warrant giving as many initial doses as possible.

“So long as there is decent efficacy after the first dose, and we have a high degree of confidence that that’s the case, in a situation where there’s only a limited supply, you want to get as many people to have as much protection as possible, as quickly as possible,” he said.

The EU has reportedly moved to require that all COVID-19 vaccine manufacturers operating in the trading bloc seek permission for any dose shipments that they plan to export. The policy comes after AstraZeneca — whose vaccine has so far been authorized in the UK — revealed that it has run into manufacturing issues that will significantly reduce vaccine deliveries to EU member states. The company said initial deliveries of the vaccine could be cut by up to 60 percent for EU nations in the first quarter. The production problems will also impact Australia’s rollout of the AstraZeneca vaccine for which it granted provisional approval yesterday in its first coronavirus vaccine authorization.

Europe as well as Canada are facing delays for Pfizer/BioNTech’s vaccine as Pfizer upgrades its Belgian manufacturing site. The company’s action, done to increase production capacity to 2 billion doses per year, generated outrage from EU member states and Canada as coronavirus cases surge across the globe (DID, Jan. 20). — James Miessler