Since week 40, the National Institute of Public Health has monitored the flu situation in Norway, and sent out weekly reports on the number of cases.
In week 43, and in the weeks up to now, FHI has mentioned a “Bangladesh-like virus that is somewhat changed from viruses we have had in Norway before”.
– The Bangladeshi virus is an H3N2 virus that has changes in the surface proteins which means that the accumulated protection we have from previous infections with H3N2 flu will not be optimal. This means that more people may become ill and some of them may get serious illness, Kjersti Rydland, head of the influenza vaccination program at FHI, explains to Dagbladet.
In the first weeks of the season, a total of 113 cases of influenza have been detected in Norway, according to FHI’s report. Last week there were 31 cases, which is the highest number in any week so far this year.
It is a predominant type A flu (H3N2). FHI has received 45 samples, of which eleven were of sufficient quality for in-depth analyzes. These, all A (H3N2), are completely genome-sequenced and are characterized as “Bangladeshi virus”.
Best protection against the flu
Has mutated
“Most viruses detected now in Europe this autumn appear to be this version of the flu,” the weekly report states.
– Is this a flu virus that has mutated, as we see with the coronavirus?
– Yes, it is. Influenza viruses mutate all the time and the H3N2 virus is the one with the highest rate of change.
Mutated influenza viruses can affect the disease picture. Rydland explains that it depends on where the mutations are. The NIPH report points out that the Bangladeshi virus has “somewhat altered antigenic properties”.
– Mutations can change the infectivity and severity of disease, and it can also affect how well our immune system can recognize it and neutralize the viruses upon exposure and infection. It is the latter that is described as antigenic properties. If the immune system does not recognize the virus and has a quick and effective response, you will be able to get sicker from new viruses, Rydland explains.
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This can affect the flu season in Norway.
– We expect that there is less degree of protection against this virus in the Norwegian population, since it is quite different from viruses that have circulated in the country before. This means that many people can get sick if this becomes the dominant virus this winter. Consequently, it could also result in more people with serious illness, she says.
Does not affect the vaccine
The FHI report also states that “the H3 component of the vaccine for the southern hemisphere was definitely changed in September from 3C.2a1b.2a1 to the new Bangladesh-like H3 virus 3C.2a1b.2a2”.
– What does that mean?
“This means that the WHO believes that the Bangladeshi virus is more likely to dominate the season in the southern hemisphere than the H3 virus that is in the vaccine of the northern hemisphere,” says Rydland.
Slaughter intensive capacity: – A castle in the air
This thus does not affect the vaccines we use in Norway.
– The vaccines we have have not been changed and will not be. It takes six months to make a vaccine, and the viruses in our vaccine were determined in February / March. Influenza vaccines are evaluated every six months for both the northern and southern hemispheres, and it is quite common for virus components to be replaced.
– Even if the vaccine is not completely matched with circulating virus and thus does not protect well against infection, they will provide protection against serious illness, she emphasizes.
Confidence plummets
1.2 million vaccinated
FHI emphasizes in the report that the incidence of influenza virus is very low in Norway today. It is nevertheless pointed out that there has been an increase in the last two weeks, which may be the first sign of increasing domestic infection in Norway.
According to the National Vaccination Register SYSVAK, 1.2 million have been vaccinated against influenza as of 7 December. In the age group over 65, the proportion vaccinated is now 62 per cent.
From week 40, FHI has registered nine new hospital admissions and fewer than five admissions to the intensive care unit with confirmed influenza.
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