Pfizer 3rd Dose: Hospitalization Prevention Effect Drops from 85% to 55% After 3 Months
A study in the United States revealed that the protective effect against hospitalization significantly decreases three months after the third dose of the COVID-19 vaccine. [Image source=Yonhap News]
[Asia Economy Reporter Kang Wooseok] A study conducted in the United States revealed that the protective effect of the COVID-19 vaccine booster against hospitalization significantly decreases after three months.
The research team at Kaiser Permanente Hospital in the U.S. announced on the 25th that additional COVID-19 vaccinations strongly protect infected individuals from the risk of hospitalization and emergency room visits during the first few months, but the level of protection weakens over time.
The study results were officially published online on the 22nd in the British medical journal The Lancet Respiratory Medicine.
Analyzing 11,123 patients who were hospitalized or visited the emergency room for reasons other than acute respiratory infections from December last year to February 6 this year, the research team confirmed that the Pfizer COVID-19 vaccine booster provided nearly 80-90% protection against hospitalization and emergency room visits after infection with the Delta or Omicron variants during the initial months, but the protective effect diminished over time.
Among patients who received the third dose less than three months ago, the vaccine prevented 85% of hospitalizations after infection, but the effectiveness dropped to 55% after three months.
Additionally, the protection against emergency room visits for the Omicron variant was 77% for patients vaccinated less than three months ago, and 53% for those vaccinated more than three months ago.
Professor Sarah Tartof of Kaiser Permanente Hospital explained, "The Pfizer COVID-19 vaccine booster significantly enhances protection against Omicron, but after three months, the protective effect against emergency room visits and even hospitalizations appears to weaken. The decline in vaccine effectiveness is similar to what was observed with the Delta variant, although the vaccine was more effective against Delta."
She added, "To maintain a high level of protection against new outbreaks potentially caused by future variants that may evade Omicron or vaccine effectiveness, additional doses of currently used vaccines or upcoming updated vaccines may be necessary."
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