Is it time to delay second doses of vaccines?

Is it time to delay second doses of vaccines?

 

Some experts are arguing that the most effective  vaccination strategy is to double the supply of  first doses by having other people delay their second doses.   Experts are pointing to real world observations to make their point. Researchers at Israel's largest hospital saw rates of infection drop 47% among more than 7,000 staff members in the two weeks following their first doses of the Pfizer-BioNTech vaccine. The two-dose vaccine regimen is taken 21 days apart. By the second to fourth week after the first shot, rates of symptomatic infection were down by 85%.   In a second example, Canadian researchers found evidence of more than 90% protection after a single dose of the Pfizer-BioNTech vaccine.   It's not at all clear how long this protection would last, and both the Pfizer and Moderna vaccines were tested and authorized on the basis of a two-dose regimen. The companies, the US Food and Drug Administration, and top government officials including National Institute of Allergy and Infectious Diseases Director Dr. Anthony Fauci have cautioned against going outside what's known and tested.   But as vaccine supply remains limited and more transmissible variants become more and more common, the race to get as many shots in arms becomes ever more crucial.