Six trials were included for vaccine efficacy (n=67,268 participants; ranging from 403 to 21,199) and 17 for adverse reactions (number of patients unclear).
The efficacy results all came from controlled clinical trials. In total there were 504 cases of pneumonia, 139 cases of severe respiratory disease and 5,956 cases of respiratory diseases other than pneumonia. Pooled estimates of protective vaccine efficacy were 41% (95% CI 30 to 51; four trials) for pneumonia, 36% (95% CI 25 to 45; six trials) for pneumonia and febrile disease, and 18% (95% CI -11 to 40; two trials) for febrile disease alone). There was no evidence of statistical heterogeneity or publication bias. Vaccine efficacy was higher when M. pneumoniae was diagnosed by serology compared with culture (54% versus 42%). Efficacy for M. pneumoniae specific protection from respiratory diseases other than pneumonia detected by serology was 51% (95% CI 3 to 75; three trials), but it was not statistically significant for culture detection. Protective efficacy against respiratory disease other than pneumonia, either alone or in combination with non-febrile disease, or non-febrile respiratory disease alone was not statistically significant.
The most commonly reported adverse effects were: pain or tenderness at the injection site (between 10 and 100% of participants); induration, erythema and nodules (between 10 and 20%) for local adjuvant alum vaccines; and general malaise or fever for systemic vaccines.