COVID-19 booster shots will be provided for medical personnel by year-end and for older people in the new year, vaccine chief Taro Kono announced Tuesday.

Japan is one of several countries that are rushing to procure and distribute supplementary doses amid mounting evidence that the antibodies provided by initial shots decline over time.

While scientists generally agree on the importance of booster shots for older people and the immunocompromised, some world-leading experts have said they do not see a need for a booster yet, arguing that the vaccines are still working well enough to prevent serious illness and death. The World Health Organization has also been calling on rich countries to refrain from rolling out booster shots and to instead give much-needed vaccines to poorer nations.

Also unclear is the ideal choice of vaccine, who will be prioritized and how the government will balance this with the inoculation of people who still haven’t received their first or second shot.

How do boosters work?

COVID-19 vaccines continue to be highly effective in limiting transmission and preventing serious illness. But the virus is evolving constantly, making countermeasures — including vaccine boosters according to many experts — necessary in order to adapt along with it.

As opposed to additional doses of the coronavirus vaccine, which help build the antibodies of an individual with a compromised or weakened immune system, booster shots bolster the immunity of someone whose antibodies have declined over time.

Vials and syringes of the Johnson and Johnson COVID-19 vaccine are displayed at a clinic in California. | AFP-JIJI
Vials and syringes of the Johnson and Johnson COVID-19 vaccine are displayed at a clinic in California. | AFP-JIJI

What is Japan’s plan?

Japan is looking to provide booster shots before the end of the year for medical personnel, and early next year for those age 65 and above. Prime Minister Yoshihide Suga has pledged that everyone who wishes to be vaccinated will have received both doses by the end of November.

According to the health ministry, the government has already secured enough doses to enable people to receive booster shots.

Inoculating the entire population is an unlikely goal, but the government aims to vaccinate as many people as possible before shifting gears to give booster shots to those who received priority inoculations earlier this year.

The inoculation of medical personnel began in February, while the inoculation of older people began in April.

Are other countries planning to administer booster shots?

Booster shots have already begun in several countries. Israel began administering such shots to individuals five months after they received their second dose, including younger people.

The U.S. Food and Drug Administration on Wednesday authorized booster shots of the Pfizer Inc.-BioNTech vaccine for people age 65 and older, and those age 18 through 64 at high risk of severe COVID-19 or who are at high risk of exposure to the virus because of their jobs. Booster shots are to be administered at least six months after an individual receives their second dose.

In Japan, it’s still unclear who will be prioritized after medical personnel and older people have received their third dose.

Citing the hugely uneven global gap in vaccine supply, WHO chief Tedros Adhanom Ghebreyesus has pushed back against booster shots for the rest of the year and called on rich nations to make the vaccine available to poor countries in Africa, where the vaccination rate remains well below 10%.

A woman is vaccinated in Nagano Prefecture in April. KYODO | KYODO
A woman is vaccinated in Nagano Prefecture in April. KYODO | KYODO

Which booster shot should you get?

The merits of mixing vaccines when getting a booster shot is the subject of heated debate.

Taking a vaccine that’s different from the one used for the first or second dose could maximize immunity, but research is still ongoing.

Combining vaccines from different manufacturers could help avoid shortages. Shortages were seen in some areas of Japan in the early stages of the vaccine rollout, when only the Pfizer shot had been approved.

Pfizer Inc., Moderna Inc. and Johnson & Johnson have all conducted studies regarding the efficacy of their booster shots. Only the vaccines by Pfizer, Moderna and Astra Zeneca PLC have been approved for use in Japan.

The U.S. Centers for Disease Control and Prevention (CDC), however, has said “a third dose of the same (messenger RNA) vaccine should be used.”

“A person should not receive more than three mRNA vaccine doses. If the mRNA vaccine product given for the first two doses is not available or is unknown, either mRNA COVID-19 vaccine product may be administered,” the CDC website says, referring to the Pfizer and Moderna shots.

The agency also said there is “limited information about the risks of receiving an additional (booster) dose of vaccine, and the safety, efficacy, and benefit of additional doses of COVID-19 vaccine in immunocompromised people continues to be evaluated.”

Will more booster shots be necessary in the future?

It’s difficult to know at this point in time what role booster shots will play in the future.

The waning protection from vaccines implies the possibility that COVID-19 will become endemic and that, much like for the flu, booster shots or something similar will need to be administered periodically.

Earlier this month, Japan laid out plans to roll back restrictions on domestic travel, dining and public events exclusively for people who have received two doses or, in some cases, those who can prove they’re not infected with COVID-19.

The need for booster shots carries heavy implications for the long-term viability of those plans to reopen society.

Vaccine chief Taro Kono speaks to reporters online on Tuesday. KYODO | KYODO
Vaccine chief Taro Kono speaks to reporters online on Tuesday. KYODO | KYODO

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