Covid-19 roundup: CDC study shows good protection from mRNA booster plus J&J's single-dose vaccine; White House launches test-to-treat Paxlovid site
Concerns about rare but life-threatening blood clots have limited the use of J&J’s Covid-19 vaccine — once pitched as the only one-shot option in the mix — with the FDA cutting it off except in limited circumstances. Yet there’s some good news for those who did receive it: A single booster dose of an mRNA vaccine for recipients of a single priming dose of Ad26.COV2.S (the J&J vaccine) provided protection close to that of a three-dose mRNA vaccine regimen.
That’s according to a new analysis from the CDC that looked at the effectiveness of four vaccination regimens during a period when Omicron was the predominant circulating variant.
They were a single priming dose of Ad26.COV2.S; a single priming dose of Ad26.COV2.S plus a booster dose of Ad26.COV2.S (Ad26.COV2.S/Ad26.COV2.S); a single priming dose of Ad26.COV2.S plus a booster dose of mRNA vaccine (Ad26.COV2.S/mRNA); and two priming doses of an mRNA vaccine plus a booster dose of mRNA vaccine (mRNA/mRNA/mRNA)
The scientists then examined testing data spanning more than 500,000 tests in order to determine the respective efficacy of these regimens. As they wrote in a letter correspondence in the New England Journal of Medicine:
Our results show that all the regimens that included a booster dose, as compared with no vaccination, offered protection against symptomatic omicron infection (the 95% confidence intervals did not include 0), although vaccine effectiveness was highest for the regimens that included a booster dose of an mRNA vaccine and was lowest for the homologous Ad26.COV2.S/Ad26.COV2.S regimen.
The results “support the current recommendation of a booster dose of mRNA vaccine at least 2 months after primary vaccination with single-dose Ad26.COV2.S or at least 4 months after an Ad26.COV2.S booster dose,” the scientists added.
White House introduces new model for distributing Pfizer’s Paxlovid
The Biden administration has launched its first test-to-treat site as part of a campaign to get more Paxlovid, the oral antiviral developed by Pfizer, into patients’ hands.
While patients currently have to get a prescription from a health provider before they can pick up a course of the drug, anyone who visits the clinic in Rhode Island will be able to get assessed by a medical provider and, if prescribed, grab their Paxlovid in one go.
The deal announcement comes as the use of Paxlovid spikes in the US, signaling not only rising case numbers but more awareness of how to access it.