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.

An experimental drug being developed by RedHill Biopharma Ltd. that improved outcomes in a randomized trial involving severely ill COVID-19 patients infected with earlier versions of the coronavirus is showing promise against the Omicron variant in test tube experiments, researchers said. Additionally, people living with well-controlled HIV infections are likely to have immune responses to the mRNA COVID-19 vaccines from Moderna and from Pfizer/BioNTech similar to those of otherwise healthy individuals, according to new data.

A year after infection with the coronavirus – when antibodies in the blood are barely detectable – the immune system continues to “remember” the virus and should respond to some extent upon re-encountering it, a study from China suggests. According to new research, women who were pregnant during the recent Omicron surge had more than eight times the rate of COVID-19 diagnoses, but lower odds of severe illness compared with pregnant women diagnosed earlier in the pandemic.

Pfizer CEO Albert Bourla raked in $24.3 million in total compensation in 2021. In other news, tinnitus (ringing or buzzing in one or both ears) might be a side effect of COVID-19 vaccines.

Lilly and Roche expressed their criticism of the draft guidance from the U.S. Centers for Medicare & Medicaid Services (CMS) for Biogen’s Alzheimer’s drug Aduhelm (aducanumab).

Merck & Co. and Ridgeback Biotherapeutics announced they have supplied about 3.1 million courses of their antiviral drug against COVID-19, molnupiravir, to the U.S. government. In other news, a study funded by the National Institutes of Health found that vaccination against COVID-19 not only protects pregnant women against the disease but their babies as well.

At 6 months of age, babies born to mothers vaccinated against COVID-19 during pregnancy are more likely to have antibodies against the virus in their blood than babies born to unvaccinated mothers who were infected while pregnant, a small study suggests. Additionally, contracting COVID-19 late in pregnancy is linked with a higher risk for obstetric complications, new data suggest.

COVID-19 vaccines using mRNA technology do not affect fertility outcomes during in-vitro fertilization (IVF), researchers found. Other new findings suggest the bacteria living in the small intestine may contribute to the risk for long COVID after infection with SARS-CoV-2.

According to a recent study conducted by researchers at Harvard Medical School and Beth Israel Deaconess Medical Center, 76 percent of the adverse side effects (such as fatigue or headache) that people experienced after receiving their first COVID-19 vaccination were also reported by participants who received a placebo shot.

Three U.S. studies show that a third dose of an mRNA vaccine is key to fighting the Omicron coronavirus variant, providing 90% protection against hospitalization due to COVID-19, the U.S. Centers for Disease Control and Prevention (CDC) said on January 21.