First, can someone who has been vaccinated still spread the disease? Second, will the vaccine remain effective as the virus itself evolves? And third, how long will the vaccine's protection last?

Emergent BioSolutions is under contract with Operation Warp Speed to make COVID-19 vaccines, but the terms could allow employees and their families to get vaccinated ahead of schedule.

As states suddenly expand the categories of people eligible for the first scarce shipments of vaccine, who will be watching to make sure those hit hardest by the pandemic aren't left behind?

The change means that doctors will no longer need a special federal waiver in order to prescribe buprenorphine, a medication to treat opioid use disorder.

The evidence is strong that some people struggling with meth addiction benefit from the drug regime.

It takes time after vaccination for immunity to the virus to build up, and no vaccine is 100% effective. Plus, scientists don't yet know if the vaccine stops viral spread. Here's what's known so far.

The federal government announced several big changes to its vaccine plans, upending earlier guidance about whom to prioritize for the next phase.

Antibody-based drugs that bind to the coronavirus to prevent it from invading cells can help patients with mild to moderate COVID-19. But the medicines can be tough to find in time.

Even if the Biden administration releases all available doses of COVID-19 vaccines, supplies will remain limited. How best to use that limited supply is a question mathematicians can help answer.

Mathematical models can help public health officials decide how best to deploy the COVID-19 vaccine when it is in short supply.

Experts argue that pushing out more COVID-19 vaccine doses to states sooner may be a good idea, even if it means there's a chance some people's second dose gets delayed.

With case and death counts still surging, the pressure is on to vaccinate as many people as possible. Here's what it will take to get more Americans their shots, fast.

President-elect Biden plans to release almost all available doses of COVID-19 vaccines, stepping away from the Trump administration policy to hold back about half of the supplies for booster shots.

To get vaccines into long-term care facilities, West Virginia was the only state to opt out of a federal partnership with CVS and Walgreens. Instead, a network of smaller pharmacies got a jump-start.

While logistical challenges have hampered use of antibody drugs to treat people with mild-to-moderate COVID-19, recent results show the medicines can be worthwhile.