Autumn is here, should I take the booster shot of the COVID-19 vaccine?


Many countries that are starting to enter autumn are rolling out booster shots to high-risk groups, but low-risk groups don't know what choices they should make.

Across the Northern Hemisphere, public health officials are rushing to deploy fall vaccination plans to prevent the possible arrival of a new batch of new coronavirus (SARS-CoV-2) mutant strains. In the UK, health authorities have brought forward the date for the latest booster shot to September 11 - a month earlier than planned. The U.S. Centers for Disease Control and Prevention (CDC) announced on September 13 that it is recommended that all people over the age of 6 months receive a booster shot of the new coronavirus vaccine.

However, there are still many countries that only recommend booster shots for people who are at higher risk of hospitalization or death, such as those aged 60 and over. So, how should large groups of people who are not at high risk choose?

Scientists believe that even without the latest COVID-19 vaccine booster shot, healthy young people and those who have been vaccinated should still have protection against severe disease. However, some researchers said that even if they do not belong to the high-risk group, one more shot can still reduce the risk of reinfection, although it can only provide short-term protection. In addition, there are other benefits.

Rafi Ahmed, an immunologist at Emory University in the United States, said: "No matter who you are, taking a booster shot of the new coronavirus vaccine will definitely be useful."

Some countries have been rolling out new booster shots over the past few years. For example, in the United States, since 2021, booster shots for low-risk groups have been launched at least twice, while booster shots for high-risk groups have been launched four times.

But the role of booster shots is also changing because many people have already been exposed to the coronavirus. In the UK, as of mid-February, at least three-quarters of the population had been vaccinated, infected with the new coronavirus, or both. In Beijing, as of the end of January, more than 90% of citizens had been infected with the new coronavirus

Today, many countries no longer adopt the policy of “universal COVID-19 vaccine booster shots”. British health authorities announced in August that autumn booster shots would only be provided to the most vulnerable groups, such as those aged 65 and over and medical workers. France does not recommend booster shots for groups other than vulnerable groups. Germany has no plans for a booster shot this fall, but recommends that high-risk groups get an annual booster shot.

The outlier here is the United States. On September 13, independent scientists advising the U.S. Centers for Disease Control and Prevention voted 13 to 1 to recommend that the new vaccine be made available to the entire population.

"We expect the latest COVID-19 vaccine booster to have benefits across all age groups," a CDC epidemiologist said before the vote. Models predict that significant numbers of hospitalizations and deaths could be avoided if the vaccine was made available to the entire population, rather than just to those 65 and older.

Researchers generally believe that because the main function of the booster shot is to prevent severe disease, high-risk groups are the group that can best benefit from the booster shot of the new coronavirus vaccine. Dan Barouch, an immunologist at Beth Israel Deaconess Medical Center in the United States, said: "For the elderly, suppressed immune systems, and people with comorbidities, it is of great significance to get a booster shot of the new crown vaccine. It is best for these people to get one every year. Above the needle.”

However, the move away from universal booster shots leaves people who are not in vulnerable groups to decide for themselves whether to get a booster shot, and scientists have mixed views on this.

Amesh Adalja, an infectious disease expert at the Johns Hopkins Center for Health Security in the United States, said that for low-risk groups, the new crown vaccine booster shot "may not be able to prevent severe disease because they are not at risk of severe disease themselves."

But he and others have also said that COVID-19 vaccine booster shots can delay infection in low-risk people, although the vaccine cannot permanently block infection. The new coronavirus vaccine booster shot can also shorten the onset of COVID-19, Ahmed said, which may reduce the spread of the virus.

Michael Osterholm, an epidemiologist at the University of Minnesota, believes that low-risk groups should have the option to get vaccinated. He pointed out that the COVID-19 hospitalization rate among American teenagers has recently increased, and parents have legitimate reasons to vaccinate their children. But he also agreed that healthy people do not need to take this booster shot. Barouch said experts are divided on whether low-risk young people should get booster shots.

Another complicating factor is new COVID-19 mutant strains, such as BA.2.86, a highly mutated Omicron descendant. Its appearance led the British health authorities to decide to launch the autumn new crown vaccine booster shot in advance. One of the new booster shots can target Omicron's XBB.1.5 subtype, which swept many countries in the first half of 2022. The vaccine recommended in the United States also targets XBB.1.5.

Recent data shows that despite previous concerns, the latest COVID-19 vaccine booster shot may be effective against BA.2.86 and its competing variants. Moderna announced last week that its vaccine targeting XBB.1.5 produces antibodies against BA.2.86 and other circulating variants. A study [2] published on the preprint server bioRxiv on September 4 showed that the antibodies of people who were infected with the new coronavirus during the spread of XBB.1.5 were active against BA.2.86. The study has not yet been peer-reviewed.

Barouch's team analyzed people infected with this XBB variant strain and found [3] that the antibody responses of these people to all variant strains increased after infection, including to BA.2.86. "This suggests that a vaccine based on XBB.1.5 should be able to induce an antibody response against all circulating variants," Barouch said. The study was published on bioRxiv on September 5 and has not yet been peer-reviewed.