Coronavirus: Global situation

US authorises 'mix and match' vaccine boosters

WASHINGTON • The US Food and Drug Administration (FDA) has authorised the use of a so-called "mix and match" strategy for people who require a booster shot of a Covid-19 vaccine.

"The FDA has determined that the known and potential benefits of a single heterologous booster dose outweigh the known and potential risks of their use in eligible populations," the agency said.

Vaccines from Pfizer, Moderna and Johnson & Johnson are authorised in the United States. A single dose of any of them may now be used following completion of primary vaccination with a different Covid-19 vaccine.

According to the new decision, people who received two Moderna shots initially and are 65 or older, over 18 and at high risk for Covid-19, or over 18 and have high occupational exposure, may now receive a booster. All adults who received the one-shot J&J vaccine more than two months ago are also eligible for a booster.

Previously, only immunocompromised people or people who belonged to elderly or high risk groups and had received the Pfizer vaccine were eligible for a boost.

The data supporting the decisions comes from emerging research reviewed by the FDA. "Today's actions demonstrate our commitment to public health in proactively fighting against the Covid-19 pandemic," said acting FDA commissioner Janet Woodcock.

The FDA also cautioned about highly rare side effects associated with the vaccines. The mRNA vaccines by Pfizer and Moderna have been associated with increased risks of inflammatory heart conditions, myocarditis and pericarditis, especially in younger males.

US administration officials, anticipating that regulators will soon make the vaccines available to those aged five to 11, have laid out plans to ensure some thousands of paediatric or primary care offices, pharmacies and school clinics will be ready to administer shots.

The campaign to vaccinate young children aims to fulfil the unique needs of patients largely still in elementary school and an age group containing more people than the teenage cohort already approved to receive the shots.

This month, Pfizer and BioNTech asked the FDA to authorise emergency use of their vaccine for those aged five to 11, a move that could help protect over 28 million people in the US. A meeting on the authorisation is set for Oct 26. An FDA ruling could come in the days after, possibly clearing a path for the Centres for Disease Control and Prevention (CDC) to make recommendations on a paediatric dose early next month.

Federal regulators have delayed authorising Moderna's vaccine for young people amid concerns of cases of rare heart problems.

"Kids have different needs than adults, and our operational planning is geared to meet those specific needs, including by offering vaccinations and settings that parents and kids are familiar with," President Joe Biden's coronavirus response coordinator Jeffrey Zients said on Wednesday, when the plan was announced. "We're going to be ready, pending the FDA and CDC decision."


A version of this article appeared in the print edition of The Straits Times on October 22, 2021, with the headline 'US authorises 'mix and match' vaccine boosters'. Subscribe