Two doses of Pfizer’s COVID-19 vaccine were 78% effective in inhibiting infection in pregnant women in Israel, according to a new research published Monday in JAMA that involved analyzing data on approximately 15,000 pregnant women, including 7500 vaccinated women and 7500 unvaccinated women matched by their age, residential area, and the number of times they have given birth to a child.
About 36% of the women were in the second trimester, and 33% were in the third trimester. The vaccinated women received their first dose between Dec. 19 and Feb. 28. Fortunately, none of the patients reported harsh harmful reactions to the vaccines.
“Vaccination compared with no vaccination was associated with a significantly lower risk for SARS-CoV-2 infection,” the authors wrote.
“Although SARS-CoV-2 infection in pregnant women is mostly without any symptoms or mild symptoms, it may result in severe complications, including admission to the intensive care unit and mechanical ventilation, particularly in the third trimester,” they wrote. “Symptomatic SARS-CoV-2 infections in women also have been linked to a greater possibility of preterm delivery and fetal intrapartum distress.”
As more time passed, the risk of infection declined for the women who had been vaccinated. The researchers estimated that, at 28 days or more after vaccination, the efficacy was 78%.
In the vaccinated group, 68 patients reported detrimental reactions, though none were severe. The most common symptoms were headache, weakness, pain, and stomachache, which didn’t last longer than a day.
The study was particularly important, the researchers said, because while the Pfizer vaccine showed 85% efficacy in preventing infection 7 days or more after the second dose in phase 3 the clinical trial, pregnant women were not included.