A single dose of Pfizer’s coronavirus vaccine may not generate a sufficient immune response to protect against dominant new variants, except in people who have already been infected with Covid-19, according to a UK study published on April 30.

BioNTech expects results by September from trials testing the Covid-19 vaccine developed with Pfizer in babies as young as 6 months old, German magazine Spiegel cited the company’s CEO as saying.

Covid-19 vaccines deployed in England can cut transmission of the coronavirus in households by up to a half, data from Public Health England (PHE) showed on April 28, in addition to the protection the shots offer against symptomatic infection.

Regeneron Pharmaceuticals announced results from the company’s Phase III trial of recently infected asymptomatic Covid-19 patients for the REGEN-COV (casirivimab with imdevimab) antibody cocktail.

China’s CanSino Biologics Inc. said the efficacy rate for the company’s single-dose Covid-19 vaccine may fall over time although it should still have a rate of 50 percent or more five to six months after inoculation.

Abbott received U.S. Food and Drug Administration Emergency Use Authorization (EUA) for over-the-counter, non-prescription, asymptomatic use of the company’s BinaxNOW COVID-19 Ag Self Test for detection of COVID-19 infection.

Pfizer Inc. and BioNTech SE said on March 10 that real-world data from Israel suggests their Covid-19 vaccine is 94 percent effective in preventing asymptomatic infections, meaning it could significantly reduce transmission.

Johnson & Johnson’s one-dose Covid-19 vaccine appeared safe and effective in trials, the U.S. Food and Drug Administration said, paving the way for approval for emergency use as soon as Feb. 26.