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Measles Vaccine · Journal article
Expert Review of Vaccines · August 14, 2026
Well-designed and adequately powered for the question it asks.
This systematic review of 33 studies documents 70 vaccinated individuals who transmitted measles, resulting in 237 direct secondary cases and 812 tertiary cases when transmission chains were traced. Although measles transmission from vaccinated cases is relatively uncommon, the pooled evidence confirms it is epidemiologically real and relevant to outbreak investigation.
Systematic review and meta-analysis. Individuals vaccinated with one or more doses of measles-containing vaccine who subsequently transmitted measles virus, identified across 33 included articles. Intervention: Receipt of one or more doses of measles-containing vaccine prior to measles transmission. n = 70.
70 individuals who had received 1 or more doses of measles-containing vaccine transmitted measles virus, resulting in 237 secondary cases Vaccinated transmitters in eliminated areas had median age 19 years (IQR: 3, 21) versus non-eliminated areas 16 years (IQR: 13, 18); p = 0.12 91% (30/33) of studies provided data on subsequent transmission generations, with 812 measles cases traced back to vaccinated individuals
Safety was not reported in the material analysed. Check the source before drawing any conclusion about harm.
Public health practitioners investigating measles outbreaks should recognize that vaccinated individuals, though less frequently, can transmit measles and contribute to outbreak propagation. Vaccination status alone does not exclude an individual as a source of transmission during epidemiological investigations.
A systematic review and meta-analysis of 33 peer-reviewed studies with clearly reported transmission frequencies and secondary case counts provides rigorous pooled evidence on an important epidemiological question, though the effect is descriptive rather than comparative.
As stated by the source record.
Quoted from the source exactly as published.
Public health practitioners investigating measles outbreaks should recognize that vaccinated individuals, though less frequently, can transmit measles and contribute to outbreak propagation. Vaccination status alone does not exclude an individual as a source of transmission during epidemiological investigations.
Graded across the dimensions that decide whether you should act, each from what the source actually supports. There is no single score, and where a dimension was not assessed it says so.
Introduction. We reviewed evidence on whether vaccinated individuals can transmit measles and conducted a meta-analysis to understand transmission characteristics.Methods. We searched and extracted data from peer-reviewed and gray literature and included studies reporting measles transmission events from vaccinated individuals. We meta-analyzed the data to calculate the median number of transmissions from vaccinated cases by measles burden, number of doses, and time since first and last dose.Results. We identified 11,911 peer-reviewed and 22 gray literature records and included 33 articles in our review. Seventy individuals who had received 1 or more doses of measles-containing vaccine transmitted measles virus, resulting in 237 secondary cases. Vaccinated transmitters in eliminated areas were older (median age of 19 years (IQR: 3, 21)) than those in non-eliminated areas (median age 16 years; IQR 13, 18) (p = 0.12). Additionally, 91% (30/33) of studies provided data on subsequent transmission generations, leading to 812 measles cases traced back to vaccinated individuals, with a median of 4 (IQR: 1, 10) cases per vaccinated transmitter.Conclusion. Measles transmissions from vaccinated cases, although relatively uncommon, must be considered in public health investigations, as such transmissions can contribute to outbreaks.
Taken from the source record, never inferred. Follow any of these and new work involving them reaches your briefing.