Surveillance bias in the assessment of the size of COVID-19 epidemic waves: a case study.

Tancredi, S; Cullati, S; Chiolero, A (2024). Surveillance bias in the assessment of the size of COVID-19 epidemic waves: a case study. Public health, 234, pp. 98-104. Elsevier 10.1016/j.puhe.2024.06.006

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OBJECTIVES

To estimate the size of COVID-19 waves using four indicators across three pandemic periods and assess potential surveillance bias.

STUDY DESIGN

Case study using data from one region of Switzerland.

METHODS

We compared cases, hospitalizations, deaths, and seroprevalence during three periods including the first three pandemic waves (period 1: Feb-Oct 2020; period 2: Oct 2020-Feb 2021; period 3: Feb-Aug 2021). Data were retrieved from the Federal Office of Public Health or estimated from population-based studies. To assess potential surveillance bias, indicators were compared to a reference indicator, i.e. seroprevalence during periods 1 and 2 and hospitalizations during the period 3. Timeliness of indicators (the duration from data generation to the availability of the information to decision-makers) was also evaluated.

RESULTS

Using seroprevalence (our reference indicator for period 1 and 2), the 2nd wave size was slightly larger (by a ratio of 1.4) than the 1st wave. Compared to seroprevalence, cases largely overestimated the 2nd wave size (2nd vs 1st wave ratio: 6.5), while hospitalizations (ratio: 2.2) and deaths (ratio: 2.9) were more suitable to compare the size of these waves. Using hospitalizations as a reference, the 3rd wave size was slightly smaller (by a ratio of 0.7) than the 2nd wave. Cases or deaths slightly underestimated the 3rd wave size (3rd vs 2nd wave ratio for cases: 0.5; for deaths: 0.4). The seroprevalence was not useful to compare the size of these waves due to high vaccination rates. Across all waves, timeliness for cases and hospitalizations was better than for deaths or seroprevalence.

CONCLUSIONS

The usefulness of indicators for assessing the size of pandemic waves depends on the type of indicator and the period of the pandemic.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Medical Education > Institute of General Practice and Primary Care (BIHAM)

UniBE Contributor:

Chiolero, Arnaud

Subjects:

600 Technology > 610 Medicine & health
300 Social sciences, sociology & anthropology > 360 Social problems & social services

ISSN:

0033-3506

Publisher:

Elsevier

Language:

English

Submitter:

Pubmed Import

Date Deposited:

08 Jul 2024 11:19

Last Modified:

10 Jul 2024 13:32

Publisher DOI:

10.1016/j.puhe.2024.06.006

PubMed ID:

38972230

Uncontrolled Keywords:

COVID-19 pandemic Epidemiology Public health SARS-CoV-2 Seroprevalence Surveillance bias

BORIS DOI:

10.48350/198640

URI:

https://boris.unibe.ch/id/eprint/198640

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