“Can We Do Twice as Many Vaccinations as We Thought?”
In an opinion piece for the NY Times, Zeynep Tufekci and epidemiologist Michael Mina are urging for new trials of the Moderna and Pfizer/BioNTech Covid-19 vaccines to begin immediately to see how effective a single dose might be in preventing new infections. If the trials do indicate that a single dose works, that would effectively double the number of people we could vaccinate within a certain time period, saving countless lives in the US and worldwide.
Both vaccines are supposed to be administered in two doses, a prime and a booster, 21 days apart for Pfizer and 28 days for Moderna. However, in data provided to the F.D.A., there are clues for a tantalizing possibility: that even a single dose may provide significant levels of protection against the disease.
If that’s shown to be the case, this would be a game changer, allowing us to vaccinate up to twice the number of people and greatly alleviating the suffering not just in the United States, but also in countries where vaccine shortages may take years to resolve.
But to get there — to test this possibility — we must act fast and must quickly acquire more data.
For both vaccines, the sharp drop in disease in the vaccinated group started about 10 to 14 days after the first dose, before receiving the second. Moderna reported the initial dose to be 92.1 percent efficacious in preventing Covid-19 starting two weeks after the initial shot, when the immune system effects from the vaccine kick in, before the second injection on the 28th day
That raises the question of whether we should already be administrating only a single dose. But while the data is suggestive, it is also limited; important questions remain, and approval would require high standards and more trials.
The piece concludes: “The possibility of adding hundreds of millions to those who can be vaccinated immediately in the coming year is not something to be dismissed.”
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