Mycoplasma pneumoniae vaccine protective efficacy and adverse reactions--Systematic review and meta-analysis

Mycoplasma pneumoniae is a leading cause of both upper and lower respiratory infections that can lead to devastating sequela. Currently no primary prevention measures are available. During the 1960s and 1970s several inactivated M. pneumoniae vaccines were tested, some with encouraging results. Here we present a systematic review and meta-analysis on the efficacy and adverse effects of M. pneumoniae inactivated vaccines. Six clinical trials were found for efficacy calculation, with a total of 67,268 subjects. Vaccine associated adverse events were described in 15 studies. The summarized efficacy of M. pneumoniae vaccines against pneumonia regardless of etiologies was 36% (confidence interval (CI(95%)) 25 -- 45). The efficacy of the vaccines against M. pneumoniae associated pneumonia was 54% (35 -- 67) or 42% (12 -- 63) depending on diagnostic approach. Results were homogeneous without publication bias. No significant adverse reactions (including autoimmune effects) were observed. This study suggests that inactivated M. pneumoniae vaccines may reduce the total rates of both pneumonia and respiratory infections by approximately 40%. We therefore suggest redeveloping M. pneumoniae vaccines, particularly for high-risk settings as well as in the general population.