Michaeleen Doucleff - NPR

Staff volunteers queue to receive a fourth dose of the Pfizer COVID-19 vaccine at Sheba Medical Center in Israel on Dec. 27, 2021, as the hospital conducted a trial of a fourth jab of the vaccine.

Who might benefit from a 4th shot — and who might not

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.
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The future of the pandemic is looking clearer as we learn more about infection

Better data is painting a more optimistic picture about immunity after a bout of COVID-19.
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A second version of omicron is spreading. Here’s why scientists are on alert.

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.
A person in a mask.

What we know about the symptoms — and the severity — of the omicron variant

Researchers are looking at data from U.S. cases to determine if the variant causes milder disease. Even if the answer is yes, they say, rates of hospitalization could be high during the surge.
A person gets tested for COVID outside.

These numbers show just how impactful the latest COVID-19 surge is

COVID-19 cases are up across the country, fueled in large part by the highly contagious omicron variant.
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A tantalizing clue to why omicron is spreading so quickly

A new study from the University of Hong Kong offers preliminary information that could explain why this new coronavirus variant may be more transmissible.

Why some researchers think the omicron variant could be the most infectious one yet

So far, scientists have limited information about omicron. But several red flags suggest that this strain of coronavirus could quickly cause surges in many parts of the world and could be the most contagious one known.
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Coronavirus FAQ: What is long COVID? And what is my risk of getting it?

One of the surprising aspects of the pandemic is that symptoms can linger months after infection. This syndrome has been called "long COVID," and it's had a profound impact on many people's lives.
A cartoon drawing of a persons head looking at germs with clocks on them.

COVID’s endgame: Scientists have a clue about where SARS-CoV-2 is headed

Pandemic predictions have been made — and then things would change. But based on models and studies (including a 1980s test that squirted virus up human noses), researchers have a new endgame thesis.

For people who got the J&J vaccine, some doctors are advising boosters ASAP

The Johnson & Johnson booster is a big issue because people who received that vaccine may need a booster more urgently than those who received the Pfizer or Moderna, according to some experts.
An illustration of antibodies attacking a coronavirus particle.

New studies find evidence of ‘superhuman’ immunity to COVID-19 in some individuals

That's how some scientists describe the findings of a series of studies looking at the antibodies created by individuals who were infected by the coronavirus and then had an mRNA vaccine.

Immunity to COVID-19 could last longer than you’d think

So, how long does immunity last after two doses of the vaccine? Six months or so? And at that point, how much protection is left over?