The World Heath Organisation has today (January 26) warned that pregnant women should not take Moderna's Covid vaccine unless they are at risk of high exposure to the virus.

In guidance published on its website, the WHO stressed the vaccine is “safe and effective in people with known medical conditions associated with increased risk of severe disease” including hypertension, diabetes, asthma, pulmonary and liver or kidney disease.

However, it said: “While pregnancy puts women at a higher risk of severe Covid-19, the use of this vaccine in pregnant women is currently not recommended, unless they are at risk of high exposure (e.g. health workers)".

The government has ordered 17 million doses of the Moderna vaccine which is expected to arrive in the country in the spring.

The WHO also said “individuals with a history of severe allergic reaction to any component of the vaccine should not take this or any other mRNA vaccine” and it should not be given to anyone under the age of 18 “pending the results of further studies.”

Studies have shown the Moderna vaccine is 92 per cent effective in protecting against Covid-19 with protection kicking in 14 days after the first dose.

The WHO said there was no evidence to suggest any of the new strains of the disease “alter the effectiveness” of the Moderna vaccine although it remains unclear whether it prevents infection and transmission.

“Immunity persists for several months, but the full duration is not yet known. These important questions are being studied,” the WHO said.