The first Americans vaccinated against COVID-19 are getting their second dose, while
There's growing debate about whether to change vaccine dosing methods — the time between shots or even the amount in each shot — to stretch scarce supplies and possibly get more people inoculated faster. But the
“Making such changes that are not supported by adequate scientific evidence may ultimately be counterproductive to public health,” concluded a strongly worded statement from the
And despite all the attention to stretching supplies, the
WHAT VACCINES ARE AVAILABLE?
That differs by country. The
Each requires two doses for full protection, either three weeks or four weeks apart depending on the vaccine.
COULD I WAIT LONGER BETWEEN DOSES?
Last week, British health officials decided it was OK to delay the second dose as long as 12 weeks. It was a huge surprise since none of the coronavirus vaccine studies were designed to test such a gap between doses.
British officials said postponing booster doses meant they could give more people at least some protection with a first shot. They said unpublished data from the
But the big question is how long partial protection from just one dose can last.
“There is no data to demonstrate that protection after the first dose is sustained after 21 days,”
Monday, the FDA agreed, saying far too few people in both the
COULD SUPPLY BE STRETCHED BY USING SMALLER DOSES?
That speculation arose when Dr.
Slaoui said it shows a lower dose sparked a good immune reaction in people ages 18 to 55, and that officials are discussing the approach with
Presumably Slaoui was referring to early-stage studies in very small numbers of people that explored which dose to put to a real test. But the FDA allowed emergency use of Moderna’s vaccine based on a 30,000-person study that found two full doses 28 days apart are about 95% protective against COVID-19 — data that's far more solid than just checking immune reactions.
Again, the FDA late Monday dismissed that dose-stretching idea. The agency said that just like the postponed boosters theory, trying such strategies without data to back them could backfire, “undermining the historic vaccination efforts to protect the population from COVID-19.”
WOULD THESE IDEAS SPEED VACCINATIONS?
It's far from clear that stretching doses will get them into people's arms any faster at this point. In the
As of Monday, more than 4.5 million people have been vaccinated out of more than 15 million doses the
If officials did stretch doses “but there’s still not uptake, then it’s not going to make a difference,"
CAN MY SECOND DOSE BE A DIFFERENT VACCINE THAN MY FIRST?
Don't mix and match, says the FDA. There's no data showing if vaccines can be interchanged.
In fact, that's why the
Recipients get a card with information about which vaccine they received and when to return for the second dose.
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