The pharmaceutical company AstraZeneca said Saturday that it had resumed its coronavirus vaccine trial in Britain after suspending it six days ago over potential safety issues but that its trials in the United States and other countries were still on hold.

The news came the same day that a competitor, Pfizer, said it was expanding the trial of its coronavirus vaccine to 44,000 people — a big increase from its previous goal of 30,000 — in an effort to recruit a more diverse group of participants and potentially cut down the time needed to get results from the trial.

Continue reading “AstraZeneca Partly Resumes Coronavirus Vaccine Trial After Halting It for Safety” →

On Friday, a team of Russian scientists published the first report on their Covid-19 vaccine, which had been roundly criticized because of President Vladimir Putin’s decision last month to approve it before clinical trials had proved it safe and effective.

In a small group of volunteers, the scientists found that the vaccine produced a modest level of antibodies against the coronavirus, while causing only mild side effects. The research has not yet shown, however, whether people who are vaccinated are less likely to become infected than those who are not.

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In planning documents sent last week to public health agencies around the country, the Centers for Disease Control and Prevention described preparations for two coronavirus vaccines they refer to simply as Vaccine A and Vaccine B. The technical details of the vaccines, including the time between doses and their storage temperatures, match well with the two vaccines furthest along in clinical tests in the United States, made by Moderna and Pfizer.

Here’s what you need to know about how the vaccines work, how they’re being tested and how they might be rolled out to the public — if, and it’s still a big if, they are proven to work.

Continue reading “What We Know About the C.D.C.’s Covid-19 Vaccine Plans” →

Seven months into the coronavirus crisis, with more than 30 vaccines rapidly advancing through the rigorous stages of clinical trials, a surprising number of research groups are placing bets on some that have not yet been given to a single person.

The New York Times has confirmed that at least 88 candidates are under active preclinical investigation in laboratories across the world, with 67 of them slated to begin clinical trials before the end of 2021.

Those trials may begin after millions of people have already received the first wave of vaccines. It will take months to see if any of them are safe and effective.

Continue reading “What if the First Coronavirus Vaccines Aren’t the Best?” →

On Feb. 26, 175 executives at the biotech company Biogen gathered at a Boston hotel for the first night of a conference. At the time, the coronavirus seemed a faraway problem, limited mostly to China.

But the virus was right there at the conference, spreading from person to person. A new study suggests that the meeting turned into a superspreading event, seeding infections that would affect tens of thousands of people across the United States and in countries as far as Singapore and Australia.

The study, which the authors posted online on Tuesday and has not yet been published in a scientific journal, gives an unprecedented look at how far the coronavirus can spread given the right opportunities.

Continue reading “One Meeting in Boston Seeded Tens of Thousands of Infections, Study Finds” →