Finland’s National Institute for Health and Welfare (THL) says that an expanded type of influenza vaccine available this autumn should be more effective in limiting outbreaks of the flu. The new vaccine is known as a quadrivalent because it combats four types of virus rather than three as last year’s trivalent jabs did. However even the four-way shots cannot prevent all infections.
In February, the World Health Organisation (WHO) recommended that quadrivalent vaccines for the 2018-19 northern hemisphere flu season target four virus types, named after the places where they were identified: the Michigan and Singapore A viruses and the Colorado and Phuket B viruses.
Based on last winter’s experiences, the Ministry of Social Affairs and Health decided to purchase a four-virus vaccine for the coming season.
“How much added benefit the quadrivalent vaccine provides depends on what kinds of viruses arrive in the country,” says Hanna Nohynek, chief physician and vaccine programme leader at the National Institute for Health and Welfare (THL).
“If we get the influenza B that only the quadrivalent [vaccine] protects against, then it will turn out to have been a sensible decision,” she told Yle on Thursday.
However she notes that the effectiveness of a vaccine cannot be ascertained until after studies of a large enough pool of patients.
“Depending when the epidemic begins, then we might get sufficient data to begin to make reliable calculations around the turn of the year or later,” Nohynek says.
However if studies here or elsewhere indicate that the vaccine is ineffective, it will be very difficult at that point to order a different kind of vaccine.
“Manufacturers started producing these shots in February and are now distributing them around the northern hemisphere. Finland will get its own in the last week of September,” she says.
No signs of flu yet
“Usually the flu season begins around the turn of the year, but last year we had the first signs of epidemic in October, and it started with the B rather than A virus,” Nohynek explains. So far this autumn there have been no diagnosed cases of influenza.
“So far it has only been seen in the southern hemisphere,” says THL virology expert Niina Ikonen.
She says that so far there has been a great variety of virus types in circulation, so it is very difficult to guess which type will eventually gain a foothold in Finland.
In recent years the annual epidemic’s peak weeks have varied in timing and length. For instance in the 2016-17 winter, the epidemic peaked in December, whereas last winter the peak weeks stretched from late December through early April. During this period, there was an exceptional number of laboratory-confirmed cases, ranging from around 1,000 to as many as 3,600 per week.
“Influenza A and B were both circulating around Finland at the same time,” Ikonen says.
She attributes some of the increase in number of lab-certified cases to a simple rise in the number of lab tests that were carried out, but still says that last winter was an exceptionally bad flu season.
Over-65s urged to get the jab
The two million doses of vaccine due to arrive in Finland later this month are reserved for those included in the national vaccination programme, administered by the THL. This includes all children between six months and six years old, anyone over 65, pregnant women, military conscripts and volunteers as well as social and healthcare professionals, those exposed to serious cases of influenza in their family or close circle, and others in risk groups due to illnesses or treatments. Others can obtain the vaccine for themselves or get it through workplace health services.
Nohynek points out that while influenza is very common, it can also be highly serious and dangerous.
“Although the vaccine is not 100 percent effective, it’s the best that we have. It’s worth getting the jab, because there is clear evidence that those who have been vaccinated are better protected than those who are not,” she tells Yle.
Nohynek and Ikonen urge everyone in the national vaccination programme to get the shot, especially those over 65 – only half of whom usually do so.