English Researchers: "Vaccine Immunity Drops by More Than 10 Percentage Points Starting 6 Months After Vaccination"

Infection Prevention Effectiveness for Elderly May Drop Below 50% by Winter
Experts Say "Booster Shot Necessity Increasing"

[Image source=Reuters Yonhap News]

[Asia Economy Reporter Kim Suhwan] Research has shown that the immune efficacy of Pfizer and AstraZeneca (AZ) COVID-19 vaccines begins to decline from the sixth month after completing vaccination. This has increased calls emphasizing the need for booster shot administration.

According to major foreign media on the 25th (local time), a study by Zoe, a UK medical research organization, found that the effectiveness of preventing COVID-19 infection after the second dose of the vaccine dropped from 88% one month after vaccination to 74% after 5 to 6 months for Pfizer. For AZ, it decreased from 77% to 67% after 4 to 5 months.

In the worst-case scenario, it is estimated that the infection suppression effect for elderly people and healthcare workers who were vaccinated early could fall below 50% by winter.

However, the researchers added that additional studies are needed as there is insufficient data for minors.

The Zoe COVID study is based on data from 1 million users collected through its own app. The research team, supported by the government and in collaboration with King's College London, developed an app last December to record vaccinations and monitor side effects and efficacy.

Tim Spector, professor at King's College London and lead researcher of the Zoe COVID study app, said in a BBC interview, "There are still many confirmed cases, and we cannot just sit back and watch the vaccine's effectiveness disappear," adding, "We urgently need to establish a booster shot administration plan."

The UK government is awaiting the decision of the Joint Committee on Vaccination and Immunisation (JCVI) regarding booster shot administration.

The US government plans to start administering booster shots from mid-September.

Professor Simon Clarke of the University of Reading analyzed, "This study shows that relying solely on vaccines cannot stop the spread of COVID-19."

In particular, concerns have been raised that existing vaccines alone may not provide sufficient immune efficacy due to the potential emergence of new variant viruses.

Earlier, research results released last week by Oxford University indicated that the immune efficacy of Pfizer and AZ vaccines against the Delta variant decreases from 90 days after completing vaccination.

Specifically, Pfizer's efficacy dropped from 85% to 75%, and AZ's from 68% to 61%.

This content was produced with the assistance of AI translation services.