Information about allergy history and vaccine composition to support questions about suitability for vaccination with Spikevax (Moderna).

Allergies or intolerances

Individuals with allergies or intolerances may ask for advice about their suitability for a Spikevax COVID-19 vaccine. In order to decide on the correct action, take a full allergy history including details of the nature of previous reaction(s) and determine if the reaction was likely or potentially a:

  • reaction to Spikevax or other COVID-19 vaccine
  • reaction to an excipient in the Spikevax vaccine
  • reaction to something else (another allergen)

Reaction to a COVID-19 vaccine

Although the manufacturer of Spikevax vaccines contraindicates use in those with a prior hypersensitivity to the active substance or to excipients in the vaccine, revaccination may still be possible and depends on the nature of the previous reaction.


If the reaction was or might have been anaphylaxis, obtain expert advice (e.g. from an allergy specialist).

On the advice of an expert give a further dose of a Spikevax COVID-19 vaccine or give an alternative COVID-19 vaccine under medical supervision in a hospital setting. See the Green Book Chapter 14a: COVID-19 for further detail about setting, choice of vaccination, pre-medication and recommended observation period.

Non-anaphylactic reaction

Give a further dose of a Spikevax COVID-19 vaccine in any vaccination setting with special precautions. See the flow chart in the Green Book Chapter 14a: COVID-19 and accompanying text for guidance on action to take, suitable vaccinations, pre-medication and recommended observation periods dependent on the type and timing of prior reaction.

Reaction to an excipient in the Spikevax vaccine

Spikevax COVID-19 vaccines are contraindicated in those with a hypersensitivity to any excipient (ingredient) in the vaccine, but revaccination may be possible on the advice of an expert (e.g. allergy specialist). Allergy to any excipient is possible, but polyethylene glycol (PEG), contained in all Spikevax vaccine preparations, is of particular importance. Excipients in each of the Spikevax vaccines are listed in the summary of product characteristics (SmPCs), see links below:


Spikevax bivalent


Polyethylene glycols (PEGs), also known as macrogols, are a group of known allergens commonly found in medicines, many household products and cosmetics. Known allergy to PEG is rare and evidence now shows PEG allergy is implicated in only a minority of allergic reactions reported following COVID-19 vaccines. The Green Book Chapter 14a: COVID-19 suggests individuals with a known or suspected PEG allergy should be referred to an expert (e.g. allergy specialist) for advice.

On the advice of an expert give a further dose of a Spikevax COVID-19 vaccine under medical supervision in a hospital. Or as an alternative, a non-mRNA COVID-19 vaccine such as Novavax, which does not contain PEG, may be given in a setting with full resuscitation facilities (e.g. hospital). For detailed information, including information on recommended observation periods and pre-medication see the Green Book Chapter 14a: COVID-19.

Reaction to other allergen(s)

Providing the individual does not have an allergy to a COVID-19 vaccine or an excipient (ingredient) in the vaccine proceed with vaccination. The Green Book Chapter 14a: COVID-19 (table 5) recommends individuals with a previous allergic reaction (including anaphylaxis) to a food, insect sting and most medicines (where the trigger has been identified) can be vaccinated in any setting with no special precautions. However, some patients may be reassured by being observed for 15 minutes post vaccination or being pre-treated with an antihistamine.

The following information may be used to reassure individuals with specific allergies, intolerances, dietary considerations or religious beliefs:


The Spikevax vaccines do not contain animal products.


The manufacturer has confirmed that Spikevax vaccines are gluten free. The SmPCs for Spikevax vaccines do not list presence of gluten.


The manufacturer has confirmed that Spikevax vaccine do not contain soy. The SmPCs for Spikevax vaccines do not list presence of nuts/soy.


Spikevax vaccines are preservative free and so do not contain thiomersal.


UKHSA Covid-19 vaccination: information for practitioners states the rubber stopper of each multidose vial of Spikevax vaccines consists of chlorobutyl (a synthetic rubber) and does not contain latex.  In addition, the manufacturer confirms latex is not present in product-contact materials used for production of Spikevax vaccines.

However, most manufacturers of injectable products advise they cannot guarantee minute amounts of latex are not contained in raw materials obtained from their suppliers.

Religious or dietary considerations

Individuals may have questions about their suitability for vaccination based on religious beliefs or dietary considerations.

Use the following information, in conjunction with information from the reaction to other allergen(s) section and SmPCs for Spikevax vaccines to support individuals with queries.

Animal- or human-derived vaccine content

The manufacturer’s information states that no materials of human or animal origin are used in the manufacture of Spikevax original. The manufacturer has confirmed that this information also applies to the bivalent formulation.

Jewish community

There is no information on Kosher certification for Spikevax vaccines.

The Conference of European Rabbis released a position statement to support vaccination.

Muslim community

There is no information on Halal certification for Spikevax vaccines.

However, the British Islamic Medical Association released a position statement to support vaccination.

Update history

  1. Content from Moderna allergy page and religions and dietary belief page updated, reformatted and merged to create one article.
  2. Published