Since starting a nationwide COVID-19 vaccination program with the Pfizer/BioNTech vaccine, rates of mechanical ventilation dropped about two-thirds among older adults with the disease in Israel, researchers found.
Rates of mechanical ventilation among COVID-19 patients age 70 and older declined 67% from fall 2020 to February 2021 compared to COVID-19 patients younger than age 50, reported Yair Lewis, MD, PhD, of Maccabi Healthcare Services in Tel Aviv, and colleagues in the Morbidity and Mortality Weekly Report on Friday.
“These findings provide preliminary evidence of the effectiveness of vaccines in preventing severe cases of COVID-19 at the national level in Israel,” the authors added.
Since COVID-19 vaccines were authorized by the FDA, researchers continue to emphasize the message that vaccines cut rates of severe disease. That’s been shown in all the vaccine trials reported thus far. But real-world data have been lacking.
Israel implemented a nationwide vaccination program with the Pfizer/BioNTech vaccine on Dec. 20, 2020, prioritizing adults ages 60 and older, healthcare workers, and those with chronic conditions putting them at risk for severe disease.
Using data from the Israeli Ministry of Health, Lewis and colleagues compared adults ages 70 and older — who had the highest two-dose vaccination coverage (84.3%) in February — to adults ages 50 and younger, who had the lowest two-dose coverage (9.9%). Rates of mechanical ventilation in these two groups during October-December 2020 were then compared to those in February 2021.
This was a small study, as 7-day average numbers of ventilated patients in the two groups never totaled more than 170.
From October-December, there were 5.8 older COVID patients receiving ventilation for each younger one. That ratio began declining in late December, coinciding with the beginning of vaccination in Israel. Seven-day rolling average numbers of ventilated older patients peaked in late January, at about 120, versus approximately 50 for younger patients.
During the study’s final few weeks, ventilation in older patients had edged down, reaching a 7-day average of 109. Meanwhile, more younger patients had been placed on ventilation, a trend that began in late December, rising from about 10 at that point to 58 in mid-February.
As of the study’s end, the ratio of ventilated older patients to younger ones stood at 1.9:1.
Lewis and colleagues couldn’t say for certain that vaccination was responsible for these trends, but they said it was plausible. “Considering the vaccination rate and the expected vaccine efficacy, this study provides preliminary evidence at the population level for the reduction in risk for severe COVID-19, as manifested by need for mechanical ventilation, after vaccination with the Pfizer-BioNTech COVID-19 vaccine,” they wrote.
The researchers acknowledged that other factors could have affected the results, including a “strict national stay-at-home order” issued Jan. 8, as well as emergence of virus variants and “possible differences in adherence to mitigation measures between the age groups.”
The authors disclosed no conflicts of interest.