"COVID-19 Second Dose Recipients Show Vaccine Effectiveness at Unvaccinated Levels After 6 Months"

Rapid Decline in Vaccine Protection Against Omicron Variant
Excellent Effectiveness in Preventing Severe Cases
77% Prevention Effect in Third-Dose Recipients with Prior Infection

A citizen is receiving a vaccine at the vaccination center set up in Sadang Sports Complex, Dongjak-gu, Seoul. The photo is unrelated to specific expressions in the article. Photo by Asia Economy DB

[Asia Economy Reporter Na Ye-eun] Amid forecasts of a COVID-19 resurgence this summer, a study has found that even if individuals have received two doses of the vaccine, without an additional booster (third dose), the vaccine does not significantly help prevent infection from the Omicron variant.

On the 20th, according to a report by the US daily LA Times, a research team from Cornell University announced these findings.

The team compared and analyzed previous infection and vaccination status of over 100,000 people, including both COVID-19 infected and non-infected individuals, in Qatar from December 2021 to February 2022. Tests conducted within 14 days after the second dose or within 7 days after the third dose were excluded from the study, as were patients who received mixed vaccine doses.

The analysis showed that patients who completed the basic two-dose COVID-19 vaccination experienced a rapid decline in vaccine protection against the Omicron variant, with effectiveness nearly indistinguishable from unvaccinated individuals after six months.

The infection prevention effect for those with prior infection was about 46%, while those who completed the basic vaccination and received a third booster dose showed a 52% infection prevention effect.

Moreover, individuals with a history of COVID-19 infection who also received the booster showed the strongest immunity, with an infection prevention effect of approximately 77%.

However, it was confirmed that even those with only two vaccine doses had excellent protection against severe progression of COVID-19.

Race Jamal Aburadad, a professor at Cornell University Medical College’s Qatar campus, stated, "Immunity weakens over time after infection or vaccination," but emphasized, "The really important point is that immunity against severe COVID-19 remains largely preserved."

The research team explained, "We found that people who only completed two doses without a third booster had infection prevention effects similar to unvaccinated individuals," adding, "As COVID-19 virus mutations accumulate, the vaccine’s ability to recognize the virus and block infection decreases."

Meanwhile, the study was published on the 15th in the medical journal New England Journal of Medicine.

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