Are Flu vaccines Kosher?

Special requirements
Last updated: 11/11/23
ANSWER BY: Dr Richard Dawood Medical Director
Date Added: 09/08/21

We would always advise you to seek appropriate religious advice, but the following facts may help:

Vaccines are made from viruses that are grown in culture (in order to yield sufficient quantities to turn into vaccines). All flu viruses need cells in which to grow.

Standard (egg-based) vaccines:

The standard flu vaccine production method is to inoculate “seed” virus into embryonated (i.e. fertilised) hens’ eggs. Hens are kosher animals, and hens’ eggs are kosher. The situation regarding embryonated hens’ eggs might be a little more complicated, but these should be kosher also – Jewish law permits eating eggs found inside a chicken, and these may well be fertilised or embryonated.

We do vaccinate a great many observant Jewish patients, who have never found themselves in difficulty about this aspect of the vaccine.

  • Having grown in culture, the virus particles are extracted, killed and purified, so it is very doubtful how much actual egg material remains in the vaccine – only a trace at most.
  • Jewish law permits anything to be done in the cause of saving a life, and the flu vaccine is certainly in this category.

Recombinant and cell-culture vaccines:

Recombinant vaccines have technical advantages over egg-grown vaccines and give better protection, however growth in cell culture is still a key part of the production method. In the case of Supemtek, our premium recombinant vaccine, the cell line is insect-derived. In the case of Flucelvax, our cell-culture vaccine, the cell line is derived from dog kidney. In our view, for both these vaccines, the same considerations apply to as in the case of Fluenz (below).

Fluenz – Nasal Flu Spray:

Fluenz – the live vaccine currently offered to children and contains traces of modified pork gelatin. It therefore raises concerns about acceptability to observant Jews, especially given that alternatives are available.

Jewish religious authorities have however concluded that Fluenz should be regarded as Kosher, since it is administered by the nose, is modified from its original form, and provides an important benefit to health. Furthermore, kosher principles are considered to apply to dietary laws and eating, not injection or inhalation for medical rather than nutritional purposes.

However there is an alternative available, children from the age of 6 months onwards can be vaccinated via the injected Quadrivalent flu jab which does not contain any gelatin.


We are happy to discuss this prior to vaccination if you have any concerns.

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