The World Health Organization (WHO) has reversed its recommendations regarding the vaccination of pregnant women against the coronavirus in the Pfizer-BioNTech and Moderna vaccines, removing its opposition to more closely resemble current CDC guidelines.

After reviewing data, independent experts said they did not recommend the Moderna vaccine be used on pregnant women unless they are health workers exposed to the virus or have medical conditions putting them at high risk.

The vaccines made by Pfizer and Moderna, while they have not been tested in pregnant women, have not shown any harmful effects in animal studies. And the technology used in the vaccines is generally known to be safe, experts said.

Less than a week after the WHO issued the warning, when more research was presented by numerous medical sources, the organization removed the pregnancy comment in the report.

Israel has included pregnant women among those getting priority access to COVID-19 vaccines.

“Based on what we know about this kind of vaccine, we don’t have any specific reason to believe there will be specific risks that would outweigh the benefits of vaccination for pregnant women.” The recommendation is now closely aligned with the CDC’s stance.

The WHO's Strategic Advisory Group of Experts on Immunization, known as SAGE, said that the vaccine should be given in two doses at an interval of 28 days, which could be extended under exceptional circumstances to 42 days.

The guidance on Moderna came several weeks after issuing their recommendations on the rival Pfizer vaccine.

"The main recommendation for the use of this (Moderna) vaccine is that based on the current elements we recommend it should be given in doses of 100 micrograms or 0.5 ml with an interval of 28 days," Alejandro Cravioto, panel chair, told a news briefing.

"This interval might be moved to 42 days but the evidence we have does not go beyond that time," he said.

WHO director of immunization Kate O'Brien said that clinical trials of the Moderna vaccine were needed on pregnant women.

"There is no reason to think there could be a problem in pregnancy, we are just acknowledging the data is not there at the moment," she said.

The WHO was liaising with Moderna on data it submitted as part of its application for WHO emergency use listing and would make a decision soon, she said, adding: "We are doing everything with Moderna to accelerate that process."

The Pfizer and Moderna vaccines, both using mRNA technology, are "very similar," except for Pfizer requiring an ultra cold chain which is difficult for some countries, O'Brien said.

"We do recommend that you use the same vaccine for your second dose that you received for your first dose," she said.

In general, the WHO did not recommend vaccination for international travelers. (Agency report)

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