Anne Mette Fløe Hvass1, Marie Norredam2, Morten Sodemann3, Marianne Kragh Thomsen4, Wejse Christian5. 1. Department of Infectious Diseases, Aarhus University Hospital, Aarhus, Denmark; Department of Social Medicine, Aarhus Municipality, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Denmark. Electronic address: anhvas@rm.dk. 2. Danish Research Centre for Migration, Ethnicity and Health, Institute of Public Health, University of Copenhagen, Denmark; Section for Immigrant Medicine, Department of Infectious Diseases, Hvidovre University Hospital, Denmark. Electronic address: mano@sund.ku.dk. 3. Migrant Health Clinic, Department of Infectious Diseases, Odense University Hospital, Denmark. Electronic address: msodemann@health.sdu.dk. 4. Department of Clinical Microbiology, Aarhus University Hospital, Aarhus, Denmark. Electronic address: marthoms@rm.dk. 5. Department of Infectious Diseases, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Denmark; Department of Public Health, Center for Global Health, Aarhus University, Aarhus, Denmark. Electronic address: wejse@ph.au.dk.
Abstract
BACKGROUND: In 2018, Europe faced the highest number of Measles cases in a decade. In Denmark, the childhood vaccination programme has a coverage of approximately 90%. To eliminate the disease, vaccine coverage needs to be above the herd immunity threshold of 95%. This can be even more difficult to obtain, when vaccination programmes break down due to war, natural disasters etc. and concern has been raised, that unvaccinated refugees could facilitate spread of measles when migrating. METHODS: In order to address this concern, we tested 513 newly arrived refugees and family reunified refugees aged between 0 and 70 years for measles IgG antibodies. The participants were tested as part of a general health assessment between May 2016 and October 2018. In the cohort, 50% were males and the majority came from Syria (55%). RESULTS: We found that 85% of the total group of refugees had immunity against measles. The 15% lacking antibodies were evenly distributed between the various countries of origin. Moreover, we found immunity to increase with age, leaving young children most vulnerable to infection, 79.9% (<19 years) vs 89.1% (≥19 years). Interview questions on previous vaccinations did not correlate to serology. CONCLUSION: Refugees have measles immunity slightly lower than the host population.
BACKGROUND: In 2018, Europe faced the highest number of Measles cases in a decade. In Denmark, the childhood vaccination programme has a coverage of approximately 90%. To eliminate the disease, vaccine coverage needs to be above the herd immunity threshold of 95%. This can be even more difficult to obtain, when vaccination programmes break down due to war, natural disasters etc. and concern has been raised, that unvaccinated refugees could facilitate spread of measles when migrating. METHODS: In order to address this concern, we tested 513 newly arrived refugees and family reunified refugees aged between 0 and 70 years for measles IgG antibodies. The participants were tested as part of a general health assessment between May 2016 and October 2018. In the cohort, 50% were males and the majority came from Syria (55%). RESULTS: We found that 85% of the total group of refugees had immunity against measles. The 15% lacking antibodies were evenly distributed between the various countries of origin. Moreover, we found immunity to increase with age, leaving young children most vulnerable to infection, 79.9% (<19 years) vs 89.1% (≥19 years). Interview questions on previous vaccinations did not correlate to serology. CONCLUSION: Refugees have measles immunity slightly lower than the host population.
Authors: Francesco Paolo Bianchi; Pasquale Stefanizzi; Giusy Diella; Andrea Martinelli; Antonio Di Lorenzo; Maria Serena Gallone; Silvio Tafuri Journal: Vaccine X Date: 2022-08-07