About 50 million people in the United States are expected to receive a coronavirus vaccine by January. But some believe that the number could effectively be doubled to 100 million without any additional production of shots, accelerating the return to normal.
Both of the Pfizer and Moderna vaccines, recently approved by the Food and Drug Administration, are supposed to be given in two doses, the first one a prime and the second a booster. The two doses of the Pfizer vaccine are to be given 21 days apart, with the Moderna at 28 days apart.
But some experts suggest that one dose may provide ample protection.
“First doses of Pfizer/Moderna vaccines are 90%+ effective after 14 days,” tweeted Dr. Keith Klugman, director of the pneumonia program at the Gates Foundation. “Most high risk lives will be saved by giving all these limited early supplies of vaccine as first doses—second doses can be given later if first dose effectiveness wanes or when supply improves.”
Last week, Florida Gov. Ron DeSantis floated the idea.
“One dose of this Pfizer vaccine they’re finding is protective,” DeSantis said. “Some argued you shouldn’t even do the booster with Pfizer right now — just get as many doses out there. I’m not sure Pfizer would agree or the FDA would agree.”
The data provided by the FDA showed that the first dose of the Pfizer vaccine became effective after about 10 days. It was about 89% effective at preventing COVID-19 infection in the period between the time the first dose was administered and the second.
Moderna broke its data down even further, showing that the first dose of the vaccine was 92.4% effective after two weeks.
Yet there are considerable hurdles to overcome, most significantly that the FDA would need to sign off on it.
The data “raises the question of whether we should already be administrating only a single dose,” wrote Zeynep Tufekci and Dr. Michael Mina in the New York Times. “But … important questions remain, and approval would require high standards and more trials.”
Tufekci, a sociologist and writer for the New York Times, and Mina, an epidemiology professor at Harvard, wrote that one-dose trials should begin immediately on people who were among the first to get vaccinated. This would include those healthcare workers and essential workers who are at a lower risk of getting a severe case of COVID-19.
Much would depend on how long the efficacy of a single dose would last before people needed the second dose. But Tufekci and Mina pointed out that there is no hard and fast rule that a second dose must be given within weeks of the first. They note that for the measles vaccine, the second dose is given years after the first. If the second dose of the coronavirus vaccine could be delayed six months to a year, according to Tufekci and Mina, “that would allow twice as many people to get vaccinated between now and later next year, accelerating herd immunity — greatly helping to end the crisis phase of the pandemic in the United States.”
