The coronavirus vaccine developed by AstraZeneca and the University of Oxford provided strong protection against Covid-19 in a large clinical trial in the United States, completely preventing the worst outcomes from the disease, according to results announced on March 22. Federal health officials from the National Institute of Allergy and Infectious Diseases, however, said on March 23 that the encouraging results may have been based on outdated and incomplete information about the vaccine’s effectiveness. AstraZeneca defended the data and said it would release fuller results within 48 hours.
In addition, the drug company Moderna has begun a study that will test its Covid vaccine in children under 12, including babies as young as six months, the company said on March 16.
In a separate study, Moderna is testing its vaccine in 3,000 children ages 12 to 17, and may have results for that age group by summer. The vaccine would then have to be authorized for use in children, so it would not be immediately available.
Finally, the United States plans to send millions of doses of the AstraZeneca vaccine to Mexico and Canada, the White House said March 18, a notable step into vaccine diplomacy just as the Biden administration is quietly pressing Mexico to curb the stream of migrants coming to the border.
Tens of millions of doses of the vaccine have been sitting in American manufacturing sites. While their use has already been approved in dozens of countries, including Mexico and Canada, the vaccine has not yet been authorized by American regulators.