Pfizer and partner BioNTech plan to ask U.S. and European regulators within weeks to authorize a booster dose of the companies’ Covid-19 vaccine, based on evidence of greater risk of infection six months after inoculation and the spread of the highly contagious Delta variant.

The World Health Organization said on Friday that it was not clear whether Covid-19 booster vaccines will be needed to maintain protection, until further data is collected.

Next year, people are likely to need an annual Covid-19 vaccination just like they need an annual flu shot. That prediction is made by researchers at six of Australia’s leading medical research institutions, based upon their study of the levels of neutralizing antibodies needed to confer protection against Covid-19.

The majority of people who have had Covid-19 are protected from getting it again for at least six months, a study published on March 17 showed, but older people are more prone to reinfection than younger people.

Almost all people previously infected with Covid-19 have high levels of antibodies for at least six months that are likely to protect them from reinfection with the disease, results of a major UK study showed.

People who have had Covid-19 are highly unlikely to contract the disease again for at least six months after their first infection, according to a British study of healthcare workers on the frontline of the fight against the coronavirus pandemic.

Antibody levels against the novel coronavirus rose and then held steady for up to four months in more than 90% of recovered Covid-19 patients in Iceland, according to a published study.

First U.S. novel coronavirus reinfection case identified in Nevada study (Reuters) – Researchers for the first time have identified someone in the United States who was reinfected with the novel coronavirus, according to a study that has not yet been reviewed by outside experts. The report, published online, describes a 25-year-old man living in Reno, […]

Two European patients were confirmed to have been re-infected with the coronavirus, raising concerns about people’s immunity to the virus as the world struggles to tame the pandemic.

A roundup of some of the latest scientific studies on the novel coronavirus and efforts to find treatments and vaccines for Covid-19, the illness caused by the virus.