Young men could be at higher risk of contracting Covid-19 than previously recognized, researchers suggested, citing computer models.

Moderna, COVID vaccine

The U.S. Food and Drug Administration authorized a third dose of Covid-19 vaccines by Pfizer-BioNTech and Moderna for people with compromised immune systems.

The mRNA vaccine from Pfizer and BioNTech may be less effective than Moderna’s against the Delta variant of the coronavirus, according to two reports posted on medRxiv on Aug. 8 ahead of peer review.

AstraZeneca’s Covid-19 vaccine carries a small extra risk of rare blood clots with low platelets after the first dose and no extra risk after the second, a study led and funded by the drugmaker showed on July 28, after worries over side effects.

Moderna Inc. is in talks with U.S. regulators to expand the size of an ongoing trial testing the company’s Covid-19 vaccines in children aged between 5 and 11 years, the drugmaker said on July 26.

A mixed vaccination of first AstraZeneca and then a Pfizer Covid-19 shot boosted neutralizing antibody levels by six times compared with two AstraZeneca doses, a study from South Korea showed.

Antibodies triggered by Sinovac Biotech’s Covid-19 vaccine decline below a key threshold from around six months after a second dose for most recipients, although a third shot could have a strong boosting effect, according to a lab study.

Sinopharm’s Covid-19 vaccine elicited weaker antibody responses against the Delta variant, based on the first published study of its effect against the more contagious version.

Although there have been discussions about using different Covid-19 vaccines in combination, World Health Organization (WHO) chief scientist Soumya Swaminathan warned against it, calling it a “dangerous trend.”

If you think you have Covid-19, it might be best to stay away from your pets, says the author of a Dutch study that found a surprising number of dogs and cats may be getting infected.