Over 15 million people in the United States, around 4.5% of the population, had received the updated COVID-19 shots by October 27, lagging behind last year s vaccinations.
Around 4 million Americans received the updated COVID-19 shots in September, even as some people have found it difficult to book vaccination appointments or find the vaccines at no cost.
The European Union is in talks with Moderna over a new supply deal for the company s COVID-19 vaccines amid concerns over a rise in infections in the region.
Pfizer has said their updated COVID-19 vaccine elicited a strong antibody response against the BA.2.86 subvariant of the coronavirus in a preclinical study.