TY - JOUR
T1 - Revaccination with measles-mumps-rubella vaccine and hospitalization for infection in Denmark and Sweden – An interrupted time-series analysis
AU - Sørup, Signe
AU - Englund, Hélène
AU - Laake, Ida
AU - Nieminen, Heta
AU - Gehrt, Lise
AU - Feiring, Berit
AU - Trogstad, Lill
AU - Roth, Adam
AU - Benn, Christine Stabell
N1 - Funding Information:
The project was supported by NordForsk [grant number 83839 ]. The funder had no role in study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the article for publication
Publisher Copyright:
© 2021 The Authors
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2022/3/8
Y1 - 2022/3/8
N2 - Background: In a previous cohort study of 4-year-old Danish children, revaccination with the live measles-mumps-rubella vaccine (MMR) was associated with a 16% reduction in the rate of hospitalization lasting two days or longer for non-measles-mumps-rubella infections. Aim: To examine if the introduction of revaccination with MMR at 4 years of age in Denmark (spring 2008) and at 7–9 years of age in Sweden (autumn 2009), at a time when there was virtually no measles, mumps or rubella cases, was associated with a reduction in the rate of hospitalization-for-infection lasting two days or longer at the population level. Methods: We included 4-year-olds in Denmark and 7–9-year-olds in Sweden. We obtained the number of hospitalization-for-infection lasting two days or longer from nationwide hospital registers. Person-years at risk were approximated from population statistics for each season and year. We performed an interrupted time series analysis using Poisson regression to estimate the change in hospitalization incidence rates following the introduction of MMR revaccination, adjusting for seasonality. We also performed analyses with control series (3-year-olds in Denmark and 4-year-olds in Sweden). Results: Comparing the incidence of hospitalization-for-infection lasting two days or longer after the introduction of MMR revaccination with the expected level without an introduction of MMR revaccination resulted in an incidence rate ratio of 1.07 (95% confidence interval [CI] = 0.89–1.28) for 4-year-olds in Denmark and 0.89 (95% CI = 0.77–1.02) for 7–9-year-olds in Sweden in analyses without controls. Analyses with controls gave similar results. Conclusion: This population-level study of the introduction of MMR revaccination in Denmark and Sweden had inadequate power to confirm or refute the findings from an individual-level Danish study of an association between MMR revaccination and a lower incidence rate of hospitalization-for-infection lasting two days or longer.
AB - Background: In a previous cohort study of 4-year-old Danish children, revaccination with the live measles-mumps-rubella vaccine (MMR) was associated with a 16% reduction in the rate of hospitalization lasting two days or longer for non-measles-mumps-rubella infections. Aim: To examine if the introduction of revaccination with MMR at 4 years of age in Denmark (spring 2008) and at 7–9 years of age in Sweden (autumn 2009), at a time when there was virtually no measles, mumps or rubella cases, was associated with a reduction in the rate of hospitalization-for-infection lasting two days or longer at the population level. Methods: We included 4-year-olds in Denmark and 7–9-year-olds in Sweden. We obtained the number of hospitalization-for-infection lasting two days or longer from nationwide hospital registers. Person-years at risk were approximated from population statistics for each season and year. We performed an interrupted time series analysis using Poisson regression to estimate the change in hospitalization incidence rates following the introduction of MMR revaccination, adjusting for seasonality. We also performed analyses with control series (3-year-olds in Denmark and 4-year-olds in Sweden). Results: Comparing the incidence of hospitalization-for-infection lasting two days or longer after the introduction of MMR revaccination with the expected level without an introduction of MMR revaccination resulted in an incidence rate ratio of 1.07 (95% confidence interval [CI] = 0.89–1.28) for 4-year-olds in Denmark and 0.89 (95% CI = 0.77–1.02) for 7–9-year-olds in Sweden in analyses without controls. Analyses with controls gave similar results. Conclusion: This population-level study of the introduction of MMR revaccination in Denmark and Sweden had inadequate power to confirm or refute the findings from an individual-level Danish study of an association between MMR revaccination and a lower incidence rate of hospitalization-for-infection lasting two days or longer.
KW - Heterologous immunity
KW - Hospitalization
KW - Interrupted time-series analysis
KW - Measles-mumps-rubella vaccine
KW - Non-specific effects of vaccines
KW - Vaccination programme
U2 - 10.1016/j.vaccine.2021.01.028
DO - 10.1016/j.vaccine.2021.01.028
M3 - Journal article
C2 - 33518465
AN - SCOPUS:85100422039
VL - 40
SP - 1583
EP - 1593
JO - Vaccine
JF - Vaccine
SN - 0264-410X
IS - 11
ER -