Coronavirus pandemic particularly reduced other respiratory tract infections last year – a clear increase in tick-borne encephalitis cases
In 2021, the coronavirus pandemic continued to affect the incidence of several communicable diseases. In particular, other respiratory tract infections were diagnosed less than usual. The information is based on the data saved in the National Infectious Diseases Register maintained by the Finnish Institute for Health and Welfare (THL).
For instance, there were significantly fewer laboratory-confirmed cases of chlamydia pneumoniae and mycoplasma in 2021. These bacteria usually cause symptoms of respiratory tract infection. Rhinovirus rates were similar as in the previous year, but no spring and autumn peaks typical to the virus were detected.
Influenza infections are particularly common in November and December and in early spring. There was no influenza epidemic in Finland during the 2020–2021 flu season, and only individual cases of influenza were reported to the National Infectious Diseases Register. Similarly, only individual notifications were submitted in autumn 2021, while more cases were found by December.
“During the coronavirus pandemic, the diagnostics of respiratory tract infections were mainly focused on coronavirus. This makes it possible that other respiratory tract infections have been left unconfirmed. The recommendations and restrictions related to the coronavirus pandemic have also prevented the spread of other respiratory tract infections”, says Tuula Hannila-Handelberg, Chief Physician at THL.
Clear increase in tick-borne encephalitis cases
The number of tick-borne encephalitis (TBE) cases has been increasing since 2019. A total of 151 cases were reported to the National Infectious Diseases Register last year, compared to 91 in 2020.
TBE infections were found especially in people spending time in nature in regions with a high incidence of tick-borne encephalitis. In the spring of 2022, the national vaccination programme for tick-borne encephalitis expanded to new areas in Kirkkonummi and Lohja.
Intestinal infection rates are also lower than usually
In 2021, the rates of bacteria causing the most common intestinal infections, such as salmonella, shigella, campylobacter and yersinia, were also lower than in previous years.
“While the countries of origin of all intestinal infections diagnosed last year are not known, it is likely that travel restrictions related to the coronavirus pandemic reduced the number of intestinal infections from abroad,” says Hannila-Handelberg.
THL is responsible for the national monitoring, prevention and control of infectious diseases in Finland. Physicians and laboratories report findings concerning infectious diseases to the National Infectious Diseases Register maintained by THL. In 2021, a total of over 579,000 findings were reported, of which nearly 425,000 findings were related to the coronavirus. Microbe- and disease-specific data is annually published on the THL website.
Additional information
Prevalence of communicable diseases in Finland in 2021 (THL)
Tuula Hannila-Handelberg
Chief Physician
THL
tel. +358 29 524 7701
[email protected]
Idil Hussein
Researcher
THL
tel. +358 29 524 7319
[email protected]
