The Janssen viral vector vaccine provides less protection than the mRNA vaccines or the protein-based Novavax vaccine, and fewer data are available on the Janssen vaccine. The data which are available show that it offers less protection against the currently circulating Omicron virus variants than is provided by the other vaccines recommended.
Vaccination with the Janssen viral vector vaccine is explicitly recommended only for persons aged 18 or over who remain unvaccinated as of autumn 2022 and who cannot receive an mRNA vaccine or the Novavax protein-based vaccine for medical reasons or who do not wish to receive such vaccines. A single dose is recommended.
The vaccine has a good safety profile. But in very rare cases, serious side effects have been seen. A small number of people have experienced a severe allergic reaction immediately after vaccination.
In addition, rare forms of thrombosis combined with a low blood platelet count (thrombosis with thrombocytopenia syndrome, or TTS) have been observed. These cases have been serious, but have occurred in only a very small number of instances (one to eight in every million vaccinations) after a vaccination with the Janssen viral vector vaccine. You will find further information on these and other very rare serious side effects on the www.swissmedicinfo.ch website.
The safety and efficacy of the vaccine are monitored continuously.
A vaccine must meet high safety, efficacy and quality standards before it can be authorised. In Switzerland, Swissmedic is responsible for authorisation: it decides whether a vaccine should be authorised. If Swissmedic is able to confirm the efficacy, safety and quality of the vaccine, it grants the marketing authorisation for Switzerland. The vector vaccine from Janssen fulfils these criteria. Swissmedic has authorised the vaccine.
You can find all the interim findings on the efficacy and safety of the vaccine on the Infovac website (available in German, French and Italian).