SARS-CoV-2 attack rate in reception and accommodation centres for asylum seekers during the first wave: Systematic review of outbreak media reports in Germany.

Objectives: Despite concerns about the impact of the severe acute respiratory syndrome corona virus (SARS-CoV-2) in refugee camps, data on attack rates and effectiveness of containment measures are lacking. We aimed to (1) quantify the attack rate of SARS-CoV-2 during outbreaks in reception and accommodation centres in Germany during the first pandemic wave, (2) assess differences in the attack rate based on containment measures, and (3) provide an overview of testing strategies, communication, conflicts, and protection measures for refugees with special needs.

Methods: Systematic web-based review of outbreak media reports (until June 2020) on confirmed SARS-CoV-2 cases in reception centres for asylum seekers in Germany using the google search engine. Reports were screened for pre-defined inclusion criteria and complemented by snowball searches. Data on facility name, location, confirmed cases, containment measures, communication, protection strategies, and conflicts was extracted for each outbreak and reporting date. Evidence synthesis: meta-analysis and negative binomial regression.

Findings: We identified 337 media reports on 101 SARS-CoV-2 outbreaks in 99 reception and accommodation centres in Germany. The pooled SARS-CoV-2 attack rate was 13.1% (95% confidence interval, CI: 9.8-16.7). Outbreak sites implementing mass quarantine ( = 76) showed higher rates (15.7; 95% CI: 11.6-20.2) compared to sites using conventional strategies (6.6; 95% CI: 3.1-11.2), yielding a rate ratio of 0.44 (95% CI: 0.27-0.72) adjusted for testing strategies, type and size of accommodation. Conflicts occurred in at least 11.8% of all outbreaks. Few sites reported specific measures to protect refugees with special needs.

Conclusion: Mass quarantine is associated with higher attack rates, and appears to be a counter-productive containment measure in overcrowded camps, but further research with individual-level data is required to rule out residual confounding. Despite available vaccines, reception centres and refugee camps should follow the available guidelines on COVID-19 response and refrain from mass quarantine if physical distancing cannot be guaranteed.