The US drug regulator authorised updated Covid-19 vaccines from Pfizer and its partner BioNTech as well as from Moderna on Monday as the country prepares to start an autumn vaccination campaign as soon as this week. A third vaccine from Novavax remains under review.
The US Food and Drug Administration approved the shots for those aged 12 and above, and authorised them for emergency use in children aged 6 months through 11 years. Advisers to the US Centers for Disease Control and Prevention are set to meet on Tuesday to discuss recommendations on who should get the vaccines this year. CDC Director Mandy Cohen said last month she expects the shots to be given annually, but not all doctors agree everyone needs them each year.
How is this year's vaccine different from last year?
Pfizer with BioNTech, Moderna and Novavax all have created new versions of their Covid-19 vaccines. Unlike last year's booster shot that included the original strain of the virus and the then-dominant Omicron variant, this year's shot targets only XBB.1.5, the predominant variant through most of 2023.
The companies have said their retooled vaccines have been shown in early testing to work against newer Omicron subvariants now circulating, including the highly mutated BA.2.86.
Should seniors, the immunocompromised and pregnant people get the shot this year?
There is broad consensus among doctors that these groups should receive at least an annual Covid-19 vaccine to protect against the virus because of their elevated risk of severe disease, hospitalisation and death. For instance, the British government's vaccine committee said only adults 65 and older and some of these other categories will be offered the shot as they are the most likely to benefit.
Should younger, healthy adults get the new vaccine?
Many doctors believe the vaccine should be recommended annually for everyone, much like influenza vaccines.
Dr William Schaffner, a Vanderbilt University infectious diseases specialist and a liaison to the CDC's Advisory Committee on Immunisation Practices, said a simple and straight-forward recommendation is likely best.
"If you're six months of age or older, you should get a flu vaccine. Sounds good to me for Covid also," Schaffner said.
Dr David Boulware, a University of Minnesota infectious diseases specialist, said he would recommend that healthy adults get the shots. According to research he has published, people who have received booster shots have symptoms that are less severe and shorter-lasting if they get sick.
Dr Paul Offit, a University of Pennsylvania infectious disease expert and a member of the FDA's vaccine advisory panel, said he believes the shots should be recommended annually only for high-risk groups. Studies have not shown the booster shots protect against disease in lower-risk populations, Offit said.
Should people suffering with long Covid get the shot?
There is some data that suggests that vaccination after infection may contribute to a reduction in long Covid symptoms. Regardless, doctors have said that a second episode of Covid-19 could rekindle prior long Covid or worsen ongoing symptoms, and vaccination could help protect against that.
Should children receive a Covid-19 vaccine this year?
Opinions vary on the need for the shots in children.
University of Minnesota epidemiologist Michael Osterholm said children made up a larger percentage of deaths and hospitalisations among those currently with Covid. Although hospitalisations in general are fairly low, over the past month people ages 17 and under have accounted for around 5-6% of Covid-19 hospitalisations, compared with around 4% on average over the previous two years, according to CDC data.
"If parents want to vaccinate their kids, they should be allowed to," Osterholm said.
Boulware said he believes giving children boosters is unnecessary unless there is an immunocompromised person in the household.
The American Academy of Pediatrics said it would make its recommendations after the CDC's advisory committee meets.