Soon, vaccine booster shots that are specific to the Omicron variant will be available in many countries. The new Omicron boosters are bivalent meaning they target two different new strains of SARS-CoV-2, the virus that causes COVID-19; in this case, the vaccine booster shots are intended to direct the body to make antibodies against the Omicron subvariants BA.4 and BA.5. Those subvariants are still circulating at high levels around the world, along with some other Omicron subvariants. This does not mean, however, that your body will be getting more mRNA in this new shot. The total mRNA content of the vaccine will remain the same as previous boosters, but it will be split between the variants.
The booster shot made by Pfizer is 30 micrograms total, and it contains 15 micrograms of mRNA against the original strain of the virus and 15 micrograms against the BA.4 and BA.5 variants. Anyone 12 and over is authorized for the Pfizer booster.
The bivalent booster made by Moderna is only authorized for people aged 18 or older right now. The Moderna booster contains 50 micrograms of mRNA; 25 micrograms for the ancestral strain and 25 for the BA.4 and BA.5 variants.
While the companies have not explained why the ancestral strain was included in the booster, one expert, Angela Branche of the University of Rochester Medical Center, suggested that they may be confronting the possibility that a new strain will emerge that is more closely related to the ancestral strain than BA.4 or BA.5.
Children who are ineligible for the Omicron-specific booster can still get the original booster shot. Pfizer is currently working to get FDA approval for the Omicron-specific booster for kids aged 5 to 11. Studies have indicated that side effects from the new booster are mild, and tend to be less severe than side effects for the original vaccine.
Everyone who is old enough has been encouraged to get the booster, and that recommendation is emphasized for people who are immunocompromised or elderly. The CDC has also noted that people who are immunocompromised should take a preventative measure called Evusheld, which is a kind of passive immunity. This is another free treatment, but requires a prescription, and the millions of people who are eligible for it may not know they can access it. If people are able to take Evusheld, they must wait two weeks for the booster shot after taking Evusheld.
Though many people have already gotten COVID-19, it's possible to be infected repeatedly. It's also worth noting that long COVID continues to impact the lives of millions of people around the world, and anyone who has had COVID-19 is at risk, even if they had a mild case. COVID-19 is also blamed for a dramatic decrease in life expectancy in the United States.
But there are some experts who have questioned the usefulness of rolling out another booster that we aren't entirely sure will prevent infection. While we know what to look for when testing flu vaccine efficacy, for example, it's more challenging to gauge the effectiveness of these vaccines that are being used against an illness we are much less familiar with, Dr. Gregory Poland of Mayo Clinic told CNN.
A pre-printed study has suggested that repeated boosters are safe and effective, however. FDA Commissioner Dr. Robert Califf is also certain that preventive measures are the best way forward. "It's just painful to see people dying unnecessarily when there's a free treatment that would prevent their death," he told CNN. "I will be at the front of the line at the pharmacy getting my vaccination," added Califf, who is turning 71 next month. "I'm very confident about this."
Some pharmacies including CVS and Walgreens have already begun scheduling appointments for people to receive the booster shot. Officials expect them to be widely available in the US within about two weeks. Right now, the booster is still available for free, although there are signals from the government that COVID boosters will not be free for much longer; free COVID tests from the US government were recently discontinued.
The Southern Hemisphere also just experienced its worst flu season in the past five years, so clinicians and scientists are urging people to also get a flu shot. It is safe to get a flu shot and a COVID booster at the same time.