db‐Stowe 2009.

Study characteristics
Methods	Self‐controlled case series, UK
Participants	Children aged 12 to 23 months with hospitalisation for bacterial or viral infections identified from hospital admission records by reviewing ICD‐9 or ICD‐10 codes (n = 2025) for the period 1 April 1995 to 1 May 2005. The present analysis of illnesses in a general population is based on an additional 10 years of data for bacterial infections and also includes admissions with viral infections.
Interventions	MMR vaccination
Outcomes	Bacterial infections: lobar pneumonia or invasive bacterial infection Viral infections: encephalitis/meningitis, herpes, pneumonia, varicella zoster, or miscellaneous virus Relative incidence of each disease was assessed within specified time risk intervals (0 to 30, 31 to 60, 61 to 90, or 0 to 90 days) after MMR immunisation.
Funding Source	Government
Notes	Conclusion: the study confirms that the MMR vaccine does not increase the risk of invasive bacterial or viral infection in the 90 days after the vaccination and does not support the hypothesis that there is an induced immune deficiency due to overload from multi‐antigen vaccines.
Risk of bias
Bias	Authors' judgement	Support for judgement
SCCS/PTC ‐ case selection	Low risk	Adequate ‐ computerised hospital record
SCCS/PTC ‐ exposure	Low risk	Adequate ‐ computerised child health and general practice records
SCCS/PTC ‐ observation and exposure risk period	Low risk	Adequate ‐ observation periods are well‐defined, exposure period appears to be well‐documented
SCCS/PTC ‐ comparability	Low risk	Adjusted for age and season
Summary Risk of Bias assessment	Low risk	Plausible bias is unlikely to have seriously altered the results.