In a peer-reviewed study published May 17 in PLOS Medicine, scientists found that mRNA-based COVID-19 vaccines were superior to adenovirus vector-based ones across major variants of the SARS-CoV-2 virus.

On May 17, the U.S. FDA authorized a booster of Pfizer’s vaccine for kids ages 5 to 11 years. The action comes as major cities are announcing a rise in cases. Additionally, COVID-19 would have claimed over 110,000 more lives in 2021 if not for the Pfizer-BioNTech vaccine, according to a Pfizer-sponsored report on the first year of the U.S. vaccination program.

A chain of events possibly triggered by unrecognized infection with the SARS-CoV-2 coronavirus could be causing the mysterious cases of severe hepatitis reported in hundreds of young children around the world, researchers suggest.

The European Center for Disease Prevention and Control said the number of unusual pediatric hepatitis cases reached 450, double the number reported two weeks earlier.

Since the emergence of the COVID-19 pandemic, there has been increased interest in developing a universal antiviral that would stop a pandemic in its tracks.

President Joe Biden on May 12 commemorated the death of 1 million people in the United States from COVID-19, marking what he called “a tragic milestone” and urging Americans to “remain vigilant” amid the ongoing pandemic.

U.S. health officials on May 6 said they are investigating 109 cases of severe hepatitis of unknown origin in children, including five reported deaths, updating a nationwide alert issued in April for doctors to be on the lookout for such cases of the liver disease.

Severe obesity may weaken the effectiveness of COVID-19 vaccines in those who have never been infected with the coronavirus, according to a small Turkish study. Additionally, South African researchers have found infection with the Omicron variant of the coronavirus can significantly improve the immune system’s ability to protect against other variants, but only in people who have been vaccinated.

The Omicron variant of the SARS-CoV-2 virus is intrinsically as severe as previous variants, unlike assumptions made in previous studies that it was more transmissible but less severe, a large study in the United States found.

Following the record surge in COVID-19 cases during the Omicron-driven wave, some 58 percent of the U.S. population overall and more than 75 percent of younger children have been infected with the coronavirus since the start of the pandemic, according to a U.S. nationwide blood survey released on April 26.