Epidemiology

Pandemic ceasefires offer an opportunity to expand vaccination efforts, experts say. But negotiation is tricky

Face coverings are essential to protecting children, keeping schools open and slowing the highly contagious coronavirus variant, experts say

Mutations that make a virus more transmissible are only part of the equation

Viral load is roughly 1,000 times higher in people infected with the Delta variant than those infected with the original coronavirus strain, according to a study in China

Current prevention measures may not be enough to prevent an outbreak

A new, more transmissible form of SARS-CoV-2 is rapidly spreading in the country and poses a threat to unvaccinated and partially vaccinated people

These pathogens already kill 1.6 million people every year, and we have few defenses against them

Mask wearing, social distancing and other steps to stop COVID-19 have also curtailed influenza

The risk of COVID transmission in schools is very low if precautions are taken

Undercounting or ignoring cases of the disease on the continent could lead to new variants that might derail efforts to end the pandemic

On the anniversary of this global disaster, we take a look back at some of the biggest mistakes, surprising successes and lingering questions

Lessons from other viruses show that even if vaccines don’t completely stop disease spread, they can still successfully contain it