Earlier this week Finland's government announced plans to dismantle restrictions that have kept people socially distanced and safer from being infected by coronavirus once 80 percent of the population is vaccinated against Covid.
But what does that mean for other contagious diseases — will the flu make a comeback as life gradually returns to normal?
The chief physician at the Institute for Health and Welfare (THL), Hanna Nohynek — who has become well-known in Finland as an expert vaccinologist during the Covid crisis — said that it's pretty likely the flu will make a comeback as people start moving around again.
"The expectation is that as society opens up and people start to travel, viruses will also travel with them. There's likely to be more influenza than there is when society is completely or mostly closed," she explained, adding however that it is difficult to say when the flu season could start.
"That really depends on when the borders open, when people travel and how many other precautions are in place, like face masks and remote working and so on. All of this affects the degree to which viruses are transmitted between people. In a normal flu season, the first individual cases would have been seen by now," she said, adding that usually influenza epidemics don't get started until the end of the year.
"There have been isolated cases and a few outbreaks, but large numbers of cases usually come after Christmas and the New Year," she explained, saying that it was very difficult to know when the flu could arrive.
Lower resistance possible
However, if and when the influenza wave does arrive, Nohynek said that due to its extended absence, people's resistance to the virus would likely be lower than under normal circumstances.
"One concern is that people have not had the flu for some time and may not be naturally protected from it," she said. "It's possible there could be an even bigger flu epidemic [than normal]. On the other hand, 1.7 million people in Finland took the flu vaccine last season. Which means they hopefully have immunological resistance."
Meanwhile, the severity of an eventual flu epidemic also depends on how well the vaccines match the antigens of the virus variant that eventually circulates.
But doing that could be challenging this year, as very few influenza types have been isolated by immunologists recently, she explained, noting that the World Health Organisation (WHO) meets twice a year to examine viruses that have been isolated around the globe.
"Based on those findings, the WHO estimates which strains are likely to be the main ones in the next flu season. This year the decision-making process has had to rely on very few [types]. Then, there is the question of whether the viruses chosen for the vaccine are the ones that will end up circulating," she said.
"At worst, an entirely new flu virus which we have very little protection against from previous years, or from an earlier vaccination, then it could be a tumultuous season ahead of us," Nohynek explained.
Double vaccinations?
The decision about which viruses to include in this season's flu vaccinations was made at the end of February.
"The WHO selected the virus strains and notified the manufacturers. We can no longer influence the vaccine's composition. Currently, some vaccines are already in the packaging phase and headed to different countries where they will be distributed soon," she said.
Flu vaccinations within public health care usually begin in November and in the private sector they start a bit later.
Like many countries around the world, Finland is planning to roll out second booster Covid vaccinations at some point as well. Nohynek said Oxford University has studied whether people will be able to take both a Covid jab and a flu vaccine at the same time.
"Based on the biological mechanisms, there's no reason to think that either vaccine would significantly interfere with each other. It's likely that both vaccines can be given at the same time," she said, adding that administering both vaccines at the same time would prevent people from having to make a second appointment to be protected.
Who should get flu jabs?
Nohynek said that previous guidance on groups that should get vaccinated would continue, in other words the flu vaccine is recommended for people belonging to risk groups, including individuals with health conditions that put them at higher risk of complications, people over the age of 65, children aged 6 months to 6 years old, expectant mothers as well as health care professionals.
She noted that being vaccinated doesn't provide 100 percent protection against a case of the flu, but does help to avoid more serious symptoms in people who do get infected.
