Persons vaccinated with Janssen will be offered an additional dose of mRNA vaccine
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The Ministry of Health and Care Services has decided to follow the National Institute of Public Health's recommendation to offer an extra dose of mRNA vaccine to those who have received one dose of the Janssen vaccine.
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- We see that full vaccination with the Janssen vaccine, which consists of one dose, seems to provide somewhat lower protection against infection and COVID-19 than those who have received two doses of an mRNA vaccine. We therefore recommend that those who have received one dose of Janssen vaccine receive a dose of mRNA vaccine to increase protection against infection with the coronavirus and against a serious course of COVID-19 illness, says Geir Bukholm, Deputy Director General at the National Institute of Public Health.
There are just over 4,000 people in Norway who have been registered as vaccinated with the Janssen vaccine in the Norwegian Immunisation Registry, SYSVAK.
- Those who want to receive an extra dose of mRNA vaccine can contact the vaccination centres in the municipality they are staying in, says Bukholm.
Degree of protection against infection and disease
Clinical studies have shown that vaccination with one dose of the Janssen vaccine provides more than 70 % protection against infection and 85 % protection against becoming seriously ill with the original virus variant (wild-type). In comparison, full vaccination with two doses of mRNA vaccine from BioNTech / Pfizer or Moderna provides 95 % protection against the same virus variant. However, when it comes to protection against serious illness, there is a smaller difference between the Janssen vaccine and the mRNA vaccines; Janssen provides 85 % protection, while mRNA vaccine provides 90-95 % protection. Preliminary results from a study in South Africa indicate that the protection against the Delta variant is lower than against the Alpha variant.
- We see that protection against the Delta variant is higher after two doses of mRNA vaccine compared to one dose. This also applies to the AstraZeneca vaccine, which is the same type of vaccine as the Janssen vaccine, says Bukholm.
Bukholm adds that studies have also shown that the immune response after a dose of the AstraZeneca vaccine can be enhanced by giving a dose of mRNA vaccine. This combination has not been shown to produce other than the usual and temporary side effects known with the use of two doses of the same vaccine.
The Norwegian Institute of Public Health recommends an interval of 8 - 12 weeks between the dose of the Janssen vaccine and a dose of the mRNA vaccine.
Consequences for a valid corona certificate
The validity of the Norwegian corona certificate is not affected. There may be different practices for how countries present supplementary vaccination after a dose of the Janssen vaccine in the corona certificate. The vaccinated person must check this before traveling.