Mix-and-match shots could simplify vaccine rollout and stimulate more-robust immune responses. Ongoing clinical trials will soon give answers.

Johnson & Johnson’s vaccine is less effective at preventing COVID-19 than other approved vaccines are, but experts say it could still be an important tool in curbing the pandemic.

The world was rocked by the COVID-19 pandemic this year, but researchers rose to all manner of challenges.

A recent study elucidates some of the changes that occur in the body after inoculation with a tuberculosis vaccine.

As researchers test existing vaccines for nonspecific protection against COVID-19, immunologists are working to understand how some inoculations protect against pathogens they weren’t designed to fend off.

A vaccine expert explains that such answers likely won’t come until a vaccine has already been approved and administered to millions of people.

Although scientists debate the ethics of deliberately infecting volunteers with SARS-CoV-2, plenty of consenting participants have been exposed to all sorts of pathogens in prior trials.

The hold will likely delay trial results, and scientists say the pause is proof that safety protocols in clinical trials are working as they should.

Some researchers express skepticism given the lack of data about the vaccine’s safety and efficacy, and the country plans to vaccinate healthcare workers, teachers, and others even before testing is complete.