ca‐Rieck 2017.
| Study characteristics | ||
| Methods | Cohort study ‐ Germany ‐ data from the German Immunisation Information Systems, also called the 'Associations of Statutory Health Insurance Physicians (ASHIPs) vaccination monitoring project'. | |
| Participants | Any individual: (i) born between January 2006 and October 2013; (ii) receiving any vaccination (i.e. not necessarily varicella) soon after birth at 0 to 4 months of age; (iii) in contact with a physician within the second half of 2015; (iv) residing at the time points of (ii) and (iii) in the region of the ASHIP that transferred the data; and (v) born in an ASHIP region where diagnosis information was available and specific vaccination claim codes for varicella vaccines had been introduced since birth. |
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| Interventions | Since 2004, single‐dose varicella vaccination has been recommended for all children aged 11 to 14 months. 2 single‐compound varicella vaccines (VAR; Varivax, Sanofi Pasteur MSD; Varilrix, GlaxoSmithKline) were initially available. In 2006, a combined MMRV vaccine (Priorix‐Tetra, GlaxoSmithKline) was licenced with a 2‐dose schedule. A universal 2‐dose schedule has been recommended since 2009, targeting children with the second dose at age 15 to 23 months. Since 2011, the first immunisation has preferably been given as 2 separate injections of VAR and MMR due to higher rates of febrile seizures following immunisation with MMRV. Catch‐up vaccinations are recommended until 17 years of age. |
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| Outcomes | Confirmed and incident varicella diagnoses | |
| Funding Source | Government | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| PCS/RCS ‐ exposed cohort selection | Unclear risk | Data from the German Immunisation Information Systems ‐ approximately 85% of the population in Germany is covered |
| PCS/RCS ‐ non‐exposed cohort selection | Unclear risk | Data from the German Immunisation Information Systems ‐ drawn from the same community |
| PCS/RCS ‐ comparability | Unclear risk | Adjusted for multivariate model ‐ vaccination status, time since vaccination ‐ probable residual confounding |
| PCS/RCS ‐ assessment of outcome | Unclear risk | There was insufficient information. |
| Summary Risk of Bias assessment | Unclear risk | We had concerns regarding at least 1 domain such that some doubt is raised about the results. |