Data continue to suggest that although the Omicron variant is more infectious and more likely to evade immunity than the Delta variant, it appears to be associated with less severe illness. Meanwhile, researchers are puzzled about the origins of Omicron.

Coronavirus vaccines are known to be less protective in people with the blood cancer multiple myeloma, such as former U.S. Secretary of State Colin Powell, who died on Oct. 18 of complications from Covid-19 despite being fully vaccinated. Additionally, in a paper in the journal Stem Cell Reports, researchers said numerous businesses have made unsubstantiated and inaccurate claims about supposed stem cell products to treat Covid-19.

People who received Johnson & Johnson’s Covid-19 vaccine will have a stronger neutralizing antibody response if they get an mRNA shot as the second dose, Axios reported on Oct. 12, citing a person who has seen data collected by the U.S. National Institutes of Health (NIH).

Moderna Inc. said on Sept. 3 the company had asked the EU drugs regulator for conditional approval of a booster shot of its Covid-19 vaccine at a 50 microgram dose.

Moderna Inc. on Sept. 1 asked the U.S. Food and Drug Administration to allow the use of a third booster dose of the company’s Covid-19 vaccine.

More studies into vaccinated populations show that although antibody responses drop months after vaccination against Covid-19, they still dramatically protect against severe disease and hospitalization. Studies are also continuing on the value and efficacy of booster shots, particularly against the Delta variant.

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.

Data from a mid-stage clinical study of an experimental vaccine candidate developed by Affinivax and Astellas Pharma for Streptococcus pneumoniae shows ASP3772 is well tolerated and generated an antibody response against the deadly bacterial infection.

A third shot of the Oxford-AstraZeneca Covid-19 vaccine produces a strong immune response, researchers said on June 28, adding there was not yet evidence that such shots were needed, especially given shortages in some countries.

Pfizer’s Covid-19 vaccine generates antibody responses three-and-a-half times larger in older people when a second dose is delayed to 12 weeks after the first, a British study said.