Suppressing corona hospitalization and death with the 4th vaccination Israel ・ Examination of more than 180,000 cases over 60 years old | Yomidokuta (Yomiuri Shimbun)

Ori Magen and colleagues from Clarit Health Services (CHS), Israel, used the new subscriber data collected by CHS, the country’s largest insurance organization with more than half of the population (more than 4.7 million people). Examining the short-term efficacy (1 month after inoculation) of 4 doses of Pfizer vaccine (Tojinameran) against coronavirus (SARS-CoV-2). As a result, the 4th inoculation group had a lower risk of SARS-CoV-2 infection, the onset and aggravation of coronavirus disease (COVID-19), and COVID-19-related hospitalization and death than the 3rd inoculation group. It was announced in Tato N Engl J Med (online version on April 13, 2022) (related article “Infection and aggravation are suppressed by 4 vaccinations”).

Compared with 3 inoculations in consideration of comorbidity

In January 2022, Israel approved the fourth vaccination for high-risk groups (60 years and older and immunocompromised persons) more than four months after the third vaccination. The latest studies have shown that 4 doses of vaccine are more effective in suppressing SARS-CoV-2 infection and COVID-19 aggravation than 3 doses. However, studies on the suppressive effects of COVID-19-related hospitalization and related death were not included in the study, and important confounding factors such as comorbidities were not adjusted.

The subjects of this analysis were those aged 60 years or older who met the conditions for the fourth inoculation from January 3 to February 18, 2022, when the Omicron strain was predominant, and who were not medical professionals with no history of SARS-CoV-2 infection. CHS subscriber. 182,122 cases (median age 72 years, 53% of women) in the 4th inoculation group, age, sex, residential area / group, 3rd inoculation month, Centers for Disease Control and Prevention (CDC) of severe COVID-19 182,122 patients in the control group (three inoculated and fourth uninoculated) matched by the number of comorbidities defined as risk factors and the number of hospitalizations in the last three years were included in the analysis.

The endpoints were SARS-CoV-2 infection (confirmed diagnosis by PCR test), symptomatic COVID-19, COVID-19-related hospitalization, severe COVID-19, COVID-19-related death, and the risk ratio between these two groups. It was calculated and the relative efficacy of the vaccine (suppressive effect of the endpoint) was verified.

COVID-19-related hospitalization and death are suppressed by around 70%

The relative efficacy of the vaccine for each endpoint 7-30 days after the 4th inoculation was 45% (95% CI 44-47%) for SARS-CoV-2 infection and 55% (same) for symptomatic COVID-19. 53-58%), 68% (59-74%) for COVID-19-related hospitalization, 62% (50-74%) for severe COVID-19, and 74% (50-90%) for COVID-19-related death. %)was. The absolute risk (number of events per 100,000 people) during the same period was 266.7 vs. control group for COVID-19-related hospitalization. The 4-dose group 86.6 (absolute risk difference 180.1, 95% CI 142.8 to 211.9), severe COVID-19 was 110.8 vs. It was 42.1 (68.8, 48.5-91.9).

The relative efficacy 14-30 days after the 4th inoculation was 52% (95% CI 49-54%) for SARS-CoV-2 infection and 61% (58-64%) for symptomatic COVID-19. 72% (63-79%) of COVID-19-related hospitalizations, 64% (48-77%) of severe COVID-19, and 76% (48-91%) of COVID-19-related deaths.

The effect of the vaccine appears from the 7th day after inoculation

In addition, as a result of analyzing the cumulative incidence curve of each evaluation item from the 4th inoculation day to 30 days after the inoculation, it was shown that the difference between the 2 groups started to increase from about 7 days after the 4th inoculation in all the items. Was done. The relative efficacy of the fourth vaccination against SARS-CoV-2 infection gradually increased from the 7th day after the inoculation, reached about 50% by the 14th day, and remained stable thereafter.

Based on the above, Magen et al. “In elderly people over 60 years old, 4 doses of Tozina melanin compared to 3 doses, SARS-CoV-2 infection, symptomatic COVID-19, COVID-19-related hospitalization, severe COVID -19, COVID-19-related death suppression effect was great. It is necessary to evaluate the long-term suppression effect in future follow-up. ” (Atsuko Ota)