Michaeleen Doucleff

Although monkeypox's recent spread has caused concern, its similarities to smallpox have given the public health world a head start on combating it.

The cases point to possible sexual transmission of this cousin of smallpox — a previously unknown method of spread for monkeypox.

During the pandemic scientists launched a vaccine in record-breaking time. Their successful use of mRNA technology could lead to progress in the decades-long effort for an HIV inoculation.

The COVID-19 pandemic is having a surprising silver lining — it's breathing new life into the fight against HIV by accelerating the development of a new type of HIV vaccine.

New versions of omicron are circulating in the United States and South Africa. Two new studies shed light on the potential for future surges — and the risk factor if you've already had omicron.

A Japanese TV show now on Netflix, 'Old Enough!,' has sparked much debate about the wisdom of allowing very young kids to be very independent. Risky? Beneficial? Child development experts weigh in.

The variants — BA.2.12 and BA.2.12.1 — have been detected in New York and other states as well as 5 other countries. One has a mutation that seems to give it an edge in evading the immune system.

My 6-year-old has been exposed to SARS-CoV-2 at least four times and never tested positive. Many people fall into that category. Researchers have theories about why they've been able to ward it off.

That's how the so-called "deltacron" variant — a mashup of delta and omicron — came to be. This process of recombining tells us a lot about the possible past and future of SARS-CoV-2.

A new coronavirus variant is a bit like Frankenstein, with the head of omicron and the body of delta. Scientists are eager to learn more about the origins of hybrid variants like "deltacron."

Two studies point to a link between the animals at the seafood market and the spread of SARS-CoV-2 — foreshadowed by photos from 2014 of raccoon dogs and birds. A top virus sleuth gives the details.

Scientists have solid, physical evidence indicating the COVID pandemic began at a seafood market in Wuhan, China. Data suggest the virus jumped from an animal at the market into people at least twice.

Some countries are moving ahead with plans to offer a fourth dose of COVID-19 vaccine. But studies are raising questions about the potential advantages of this extra booster.

Scientists now know that the potency of the booster shot wanes quickly after about three months. We look at the latest research on a fourth shot.

Answer a few questions and find out what kind of immune cell you'd be — and learn more about these amazing cells that fight off infection.

The family history of SARS-CoV-2 is not what virologists expected — and it sheds light on the coronavirus that launched a pandemic. Check out our illustration of the virus's family tree.

Scientists are beginning to come up with answers to the question of how long antibodies from an infection can protect you — and what they'll protect you from.

It's a sibling of the first omicron variant that swept the world. Is it more contagious? Does it cause severe disease? Will it keep current omicron surges going? Researchers are looking for answers.

Another version of omicron is spreading in Asia and parts of Europe. And it shows signs that it could be slightly more contagious than omicron. Where did this new variant come from?

Researchers in the U.K. have the first estimates for how long a third shot of the Pfizer vaccine will last. The findings are mixed.