Outside the usual rangeWeek 21 of 2025 (19–25 May)Outbreaks
Kerala: 9 hepatitis A and E outbreaks in the 4 weeks to week 21 of 2025, against a median of 1 for the same weeks in 2022–24.
What happened
- 4 weeks to week 21 of 2025 (19–25 May)
- 9
- That week alone: 2
- median of the same 4 weeks, 2022–24
- 1
- Change
- +8
- Change, per cent
- +800%
Why it matters
A single week of outbreak reports holds only a handful of events, too few to compare. So the observatory adds up the four weeks to this one and compares the total with the median of the same four weeks in up to three earlier years; the baseline is short because reporting itself has grown. Only rises are flagged, and only when the total is at least 5 above that median, because a fall in reported outbreaks mostly means that reports did not arrive. These are outbreaks reported to IDSP, so they reflect reporting as well as disease.
For hepatitis A and E outbreaks, neither a rise nor a fall is better in itself, so the observatory marks this movement as unusual rather than good or bad.
Historical context
Same four weeks: 2024 6, 2023 0, 2022 1. The preceding four weeks: 7. Counts are outbreaks reported to IDSP, which reflect reporting as well as disease.
The underlying data
| Period | Value | Release | Where in the document |
|---|---|---|---|
| Week 21 of 2025 | 2 | IDSP weekly outbreak report, 2025 week 21 (2025-05-19 to 2025-05-25) | IDSP weekly outbreak report 2025-W21, count over 2 rows for Kerala: p.9 KL/KAS/2025/21/892, p.10 KL/KOL/2025/21/893 |
| Week 20 of 2025 | 2 | IDSP weekly outbreak report, 2025 week 20 (2025-05-12 to 2025-05-18) | IDSP weekly outbreak report 2025-W20, count over 2 rows for Kerala: p.8 KL/KOZ/2025/20/843, p.9 KL/PAL/2025/20/845 |
| Week 19 of 2025 | 2 | IDSP weekly outbreak report, 2025 week 19 (2025-05-05 to 2025-05-11) | IDSP weekly outbreak report 2025-W19, count over 2 rows for Kerala: p.9 KL/KOT/2025/19/804, p.15 KL/MAL/2025/19/821 |
| Week 18 of 2025 | 3 | IDSP weekly outbreak report, 2025 week 18 (2025-04-28 to 2025-05-04) | IDSP weekly outbreak report 2025-W18, count over 3 rows for Kerala: p.11 KL/IDU/2025/18/759, p.12 KL/KAN/2025/18/760, p.14 KL/WAY/2025/18/765 |
| Week 21 of 2024 | 3 | IDSP weekly outbreak report, 2024 week 21 (2024-05-20 to 2024-05-26) | IDSP weekly outbreak report 2024-W21, count over 3 rows for Kerala: p.11 KL/CNR/2024/21/1005, p.12 KL/KAS/2024/21/1006, p.12 KL/WYN/2024/21/1007 |
Source and method
- Release
- IDSP weekly outbreak report, 2025 week 21 (2025-05-19 to 2025-05-25)Archived fileOriginal URLFirst seen 3 Oct 2026
More signals for hepatitis A and E outbreaks in Kerala
- Kerala: 14 hepatitis A and E outbreaks in the 4 weeks to week 21 of 2026, against a median of 6 for the same weeks in 2023–25.
- Kerala: 15 hepatitis A and E outbreaks in the 4 weeks to week 20 of 2026, against a median of 6 for the same weeks in 2023–25.
- Kerala: 6 hepatitis A and E outbreaks in week 20 of 2026, the most since week 28 of 2025.
- Kerala: 8 hepatitis A and E outbreaks in the 4 weeks to week 5 of 2026, against a median of 3 for the same weeks in 2023–25.
- Kerala: 10 hepatitis A and E outbreaks in the 4 weeks to week 51 of 2025, against a median of 3 for the same weeks in 2022–24.
- Kerala: 9 hepatitis A and E outbreaks in the 4 weeks to week 50 of 2025, against a median of 2 for the same weeks in 2022–24.
Cite this
According to the India Health Observatory, Kerala: 9 hepatitis A and E outbreaks in the 4 weeks to week 21 of 2025, against a median of 1 for the same weeks in 2022–24. Source: Integrated Disease Surveillance Programme, National Centre for Disease Control, MoHFW, IDSP weekly outbreak report, 2025 week 21 (2025-05-19 to 2025-05-25). https://indiahealthobservatory.com/signals/hepatitis-outbreaks--kerala--2025-w21--baseline_breach
See also Kerala and 2 in context.