Background.Administration of convalescent plasma, serum, or hyperimmune immunoglobulin may be of clinical benefit for treatment of severe acute respiratory infections (SARIs) of viral etiology. We conducted a systematic review and exploratory meta-analysis to assess the overall evidence. Methods.Healthcare databases and sources of grey literature were searched in July 2013. All records were screened against the protocol eligibility criteria, using a 3-stage process. Data extraction and risk of bias assessments were undertaken. Results.We identified 32 studies of SARS coronavirus infection and severe influenza. Narrative analyses revealed consistent evidence for a reduction in mortality, especially when convalescent plasma is administered early after symptom onset. Exploratory post hoc meta-analysis showed a statistically significant reduction in the pooled odds of mortality following treatment, compared with placebo or no therapy (odds ratio, 0.25; 95% confidence interval,. 14-.45; I2 = 0%). Studies were commonly of low or very low quality, lacked control groups, and at moderate or high risk of bias. Sources of clinical and methodological heterogeneity were identified. Conclusions.Convalescent plasma may reduce mortality and appears safe. This therapy should be studied within the context of a well-designed clinical trial or other formal evaluation, including for treatment of Middle East respiratory syndrome coronavirus CoV infection.
Bibliographical noteFunding Information:
Financial support. This work was supported by the WHO Pandemic and Epidemic Diseases Department.
Potential conflicts of interest. W. S. L. has received funding from the National Institute for Health Research to set up a pandemic influenza clinical trial and has received unrestricted funding from Pfizer for a study in adult pneumonia. The University of Nottingham Health Protection Research Group (with which J. S. N.-V.-T. and C. R. B. are affiliated) is an official WHO Collaborating Center for pandemic influenza and research and receives limited funding from the WHO in support for specific activities. All other authors report no potential conflicts.
© 2014 © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America.
- MERS coronavirus
- convalescent plasma
- severe acute respiratory infection
- systematic review