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.

Vaccine experts divided on whether that level of protection is too low or too demanding.

Engineered Plasmodium parasites form the basis of two experimental malaria vaccines that showed safety and encouraging immune responses in clinical trials.

The idea of deliberately infecting volunteers with SARS-CoV-2 has garnered significant attention as a potential avenue to speedier development, as the World Health Organization weighs in with recommendations.