Adaptation of COVID-19 vaccines to new SARS-CoV-2 variants


To ensure that the COVID-19 vaccines already authorised remain effective in the long term, it may be necessary to modify them. For this purpose, their composition is changed in such a way that they are effective against new or multiple variants of the SARS-CoV-2 coronavirus.

For public-health reasons and based on scientific considerations, Swissmedic does not regard such modified vaccines as requiring a new authorisation with the associated need for comprehensive clinical trials. In keeping with the principle applied to the seasonal updating of influenza vaccines, modifications relating to the exchange or addition of a serotype, a strain, an antigen or a coded region – or a combination of serotypes, strains, antigens or coded regions – made to a vaccine against the human coronavirus are classified in regulatory terms as type II variations. The assessment and authorisation process may take place on a rolling submission basis and, where appropriate, the decision may be a temporary one. Once authorised, the modified vaccine is given a new authorisation number and a new medicinal product name to differentiate it from the original vaccine.

Regarding the requirements in terms of scientific documentation, Swissmedic refers to the “Guidance for Adapting Authorised Covid-19 Vaccines for SARS-CoV2 Mutations in an Ongoing Pandemic” in the ACCESS Consortium’s “points to consider” document.

The requirements to be met with regard to the SARS-CoV-2 variants are now described in section 8 of the guidance document Authorisation procedures for COVID-19 medicinal products in pandemics. The adapted guidance document comes into effect on 15 May 2021.