Compiled by the ENCLAI research team following a documented methodology · Editorial oversight: Dr Natalya Mathur, Founder · Data last updated: (UTC)

Adenovirus infection in Finland: 2026 cases and outbreak reports

Reported adenovirus infection surveillance for Finland (FIN) — ▲ Rising · 2025 — latest record 2026-11-07

What the 2026 data shows

As of 1 November 2026, Finland has reported 1,847 adenovirus infection cases in 2026, compiled from figures published by Terveyden ja hyvinvoinnin laitos (Finnish Institute for Health and Welfare). The full year 2025 closed at 2,217 cases. 2025 closed 50% above the 2023–2024 average, which is why the trend reads “Rising”.

Of the 3 countries reporting adenovirus infection to ENCLAI in 2026, Finland accounts for 44.4% of reported cases and ranks 2 by case count.

ENCLAI has logged 722 surveillance records for adenovirus infection in Finland in 2026, with the most detailed reporting in May 2026 (626 records). 34 of those arrived in the last 30 days; the case counts run to 2026-11-01. 1 distinct surveillance sources reported this pair in 2026.

Reporting authorities for these counts: Terveyden ja hyvinvoinnin laitos (Finnish Institute for Health and Welfare)

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Surveillance summary

2026 cases (YTD)
1,847
2025 cases (full year)
2,217
Baseline avg (3yr)
N/A
Trend (2025)
▲ Rising · 2025
+50% vs 2023–2024 average

Reported cases by year, Finland

YearReported casesShare of worldwide reports
2023 445 30.9%
2024 2,511 100.0%
2025 2,217 100.0%
2026 (year to date) 1,847 44.4%

Reporting bounds and case definitions vary; historical baselines are a separate comparison measure. Worldwide share compares this country's reported figure with the sum of all countries reporting adenovirus infection to ENCLAI for that year. "Incomplete year" means our sources cover less than ten months of that year, so no full-year figure is shown; "outbreak total to date" is a running total since an outbreak began, not a count for one year.

Surveillance records logged in 2026

MonthRecordsReporting sources
May 20266261
Jun 2026121
Aug 2026301
Sep 2026201
Oct 2026251
Nov 202691

A record is one dated surveillance publication or one row of an official table; a month with many records is a month with detailed reporting, not necessarily more cases. 34 records were logged in the last 30 days.

Sub-national reporting, 2026

Areas within Finland with the most adenovirus infection records this year:

AreaRecords
Uusimaa70
North Ostrobothnia42
North Savo42
Pirkanmaa42
Southwest Finland42

Adenovirus infection in other countries, 2026

Country2026 casesTrend
Norway 2,301
Bermuda 13

Other diseases reported in Finland, 2026

Disease2026 casesTrend
Seasonal influenza 24,771 ▲ Rising · 2025
Chlamydia infection 5,488 ▼ Declining · 2025
Respiratory syncytial virus infection 4,364 ▲ Rising · 2025
Norovirus gastroenteritis 3,289 ▲ Rising · 2025
COVID-19 2,938 ▼ Declining · 2025

Questions about this page

How many adenovirus infection cases has Finland reported in 2026?
As of 1 November 2026, Finland has reported 1,847 adenovirus infection cases in 2026, compiled from figures published by Terveyden ja hyvinvoinnin laitos (Finnish Institute for Health and Welfare). The full year 2025 closed at 2,217 cases. 2025 closed 50% above the 2023–2024 average, which is why the trend reads “Rising”.
Is adenovirus infection rising or falling in Finland?
ENCLAI's trend reading for adenovirus infection in Finland is “Rising · 2025”: the latest complete year is compared with the earlier baseline from the reported counts; the current year is not judged until it closes.
Where does Finland publish adenovirus infection surveillance data?
The counts on this page were published by Terveyden ja hyvinvoinnin laitos (Finnish Institute for Health and Welfare). ENCLAI compiles and normalises them and is not affiliated with these authorities.

About this data

Figures are reported case counts as published by the originating health authorities, compiled by ENCLAI from 444 verified surveillance sources. Finland figures reflect the reporting available to ENCLAI; reporting periods and case definitions differ between sources, and a missing report does not establish zero cases. ENCLAI holds adenovirus infection records for Finland dated from 2023. How we verify and update data: methodology & Trust Center · understanding case counts.

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