The human medicines committee (CHMP) at the European Medicines Agency (EMA) has issued a reflection paper outlining the requirements for manufacturers planning to modify their COVID-19 vaccines in order to address SARS-CoV-2 variants.

Viruses typically mutate and several variant strains of SARS-CoV-2 have already been identified worldwide.

Mutations may impact on the disease transmission or severity as well as on the effectiveness of diagnostics, therapeutics or vaccines.

For more detail information, consult the Centers for Disease Control and Prevention dashboard, reporting also the geographical distribution of the SARS-CoV-2 variants.

The three authorised COVID-19 vaccines provide protection against the variants that are currently prevalent across Europe. However, it appears that with continued mutations and new variants emerging, authorised vaccines may need to be adapted to ensure continued protection. Initial data indicates that some of these variants may have an impact on the level of protection provided by COVID-19 vaccines against infection and disease.

Therefore, it is an urgent public health priority to define an expedited regulatory process for the adaptation of vaccines to protect against current or future variants.

The EMA reflection paper details the laboratory (non-clinical), clinical, quality and manufacturing data required to support the approval of ‘variant’ vaccines whether monovalent or multivalent.

According to this guidance, a new variant vaccine would largely rely on the same technology and platform as the already approved ‘parent’ vaccine. The difference would be in the specific antigen selected to trigger the immune response in the body.

In terms of clinical data, large-scale safety and efficacy studies are not needed and moreover would present feasibility constraints. The efficacy of variant vaccines should therefore be demonstrated in immunogenicity studies that are designed to investigate the immune response triggered by the variant vaccine against the variant virus.

Manufacturers should also study the efficacy of the variant vaccine when given as a single dose, as a booster, to subjects previously vaccinated with the parent vaccine.

Post-authorisation studies will be set up to monitor the long-term safety and effectiveness of variant COVID-19 vaccines.

No further laboratory studies are required to support the development of variant vaccines. However, if the applicant conducts such studies, the results will be evaluated by CHMP together with clinical data.

Moreover, the manufacturer will need to generate data on the compliance with the quality standards set for the parent vaccine. For a multivalent vaccine, containing different viral variant strains, additional evidence may be required to ensure the quality of the active substances and the finished product.

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