Doctors have urged religious communities that do not eat pork to consider making exceptions when it comes to vaccines containing gelatine.

There are several vaccines administered in the UK that contain porcine, which is made from pig’s collagen.

In the case of Fluenz Tetra – a nasal spray that protects children against flu – there is no non-gelatine alternative available.

Catherine Heffernan, principal advisor for early years, immunisations and vaccination services at NHS England, told Harrow Council’s health and well-being board that this is a sensitive but important subject.

“Of course, this is a personal choice and we have representatives who are very skilled at explaining the situation,” she said.

“This is a medicine which can be considered different from ingesting food and, currently, there is no alternative for the [nasal] flu vaccine – though there may be in the future.”

Harrow has an above average number of Jewish and Muslim residents – groups who traditionally avoid pork products – as well as a large Hindu population, which may follow a vegetarian diet.

Dr Heffernan explained that the NHS has spoken with rabbis across England to discuss the use of porcine vaccinations, particularly among orthodox communities.

When the flu vaccine was first introduced in 2013, Rabbi Abraham Adler, of the Kashrus and Medicines Information Service, said: “It should be noted that, according to Jewish laws, there is no problem with porcine or other animal derived ingredients in non-oral products.

“This includes vaccines, including those administered via the nose, injections, suppositories, creams and ointments.”

The Muslim Council of Britain said that, according to Islamic law, porcine vaccines are not permitted unless lives are at risk and there is no alternative option.

However, it encouraged Muslims to consult medical professionals if they have any concerns about their or their children’s health in relation to the flu vaccine.