Protection against an increased risk of pregnancy complications is provided by the COVID-19 Omicron booster vaccine, according to a new study at the University of Oxford in the UK and the Hadassah-University Medical Center in Jerusalem.
The main researcher from Israel, Dr. Michal Lifshitz – a nurse researcher in the obstetrics and gynecology division at the Hadassah’s Faculty of Medicine – said that “Israel was the pioneer in calling on pregnant women to vaccinate against the pandemic, and the rate of women vaccinated with a third vaccination is among the highest in the world. We are witnessing that the rate of pregnant women in Israel who were severely ill is among the lowest in the world.”The findings of an international collaboration led by the Oxford Maternal and Perinatal Health Institute (OMPHI) at the University of Oxford, together with researchers from Hadassah and other leading international centers, published research findings that aroused great interest in the leading journal, The Lancet. It has just been published under the title “Pregnancy outcomes and vaccine effectiveness during the period of omicron as the variant of concern, INTERCOVID-2022: a multinational, observational study.”Researchers at 41 medical centers in 18 countries assessed the Omicran COVID-19 variant on mothers and newborns by studying 1,545 pregnant women diagnosed with the variant and 3,073 pregnant women who were not diagnosed with the infection as controls.The study was conducted between November 27, 2021, and June 30, 2022, when Omicron was the most common strain. Vaccine effectiveness against the variant was also assessed.The study found that infection with the Omicron variant during pregnancy is connected with increased risks of maternal illness, severe pregnancy complications, and admission to the hospital, especially among symptomatic and unvaccinated women.
Also rising is the risk of preeclampsia – a serious medical condition that usually occurs about midway through pregnancy (after 20 weeks) causing high blood pressure, protein in their urine, swelling, headaches and blurred vision. Obese/overweight women with severe symptoms were at the highest risk for maternal morbidity and severe complications.
It was also found that vaccinated women were better protected against severe COVID-19 symptoms and complications and had a low risk of admission to an intensive care unit. To prevent severe COVID-19 symptoms and complications, women should be encouraged to fully vaccinate, preferably with a booster dose as well.
Preventing severe symptoms
In the study, mRNA vaccines were most effective in preventing severe COVID-19 symptoms and complications, although viral-vector vaccines also provided adequate protection – for at least 10 months after the last dose – for both types of vaccine.
“We have presented robust, evidence-based information on the increased risk of the COVID-19 Omicron variant during pregnancy for severe maternal complications among symptomatic and unvaccinated women,” according to Perinatal Medicine Prof. José Villar at Oxford, who co-led INTERCOVID 2022.“Of concern is that severe symptoms of the disease occurred in four percent to seven percent of unvaccinated women diagnosed with the COVID-19 Omicron variant during pregnancy,” he said. “The study clearly indicates the need for a full vaccination course during pregnancy, preferably with a booster, to provide protection for at least 10 months following the last dose. Antenatal services worldwide should strive to include vaccination against COVID-19 in the routine care of pregnant women.”Oxford Fetal medicine Prof. Aris Papageorghiou, who also co-led INTERCOVID 2022, concluded: “Although the Omicron variant may be less harmful than previous variants in the general population, the large proportion of unvaccinated pregnant women worldwide are still at major risk for severe illness. As it is impossible to predict who will develop severe symptoms or complications, universal full vaccination is required. Unfortunately, full vaccination coverage among pregnant women is still inadequate, even in developed countries.”