PRISMA Systematic Review Protocol Essential for Valid, Actionable Results

Dr Kerrigan et al’s article “What Barriers Exist in the Minds of Vaccine-Hesitant Parents, and How Can We Address Them?”¹ covers a topic of critical importance. The authors state that their aim was to “systematically analyze available literature,” but their methodology did not adhere to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses)² standards of a systematic review. If the authors’ intent was to rigorously answer this clinical question, following standard systematic review protocol would have increased the accuracy of their findings.

Dr Kerrigan et al did not specifically state that they conducted a systematic review in their title or article, but the statement “systematically analyze” in their abstract, in conjunction with a PRISMA flow diagram,³ suggests their overall goal was similar. If their intent was to conduct a comprehensive search of available literature to answer their question, following systematic review methodology would have best accomplished that task. A systematic review “attempts to identify, appraise and synthesize all the empirical evidence that meets prespecified eligibility criteria to answer a specific research question.”⁴ Performing a systematic review requires adherence to “explicit, systematic methods that are selected with a view aimed at minimizing bias, to produce more reliable findings to inform decision making.”⁴ They did not search all available literature, as they only examined one database with four search terms. They did not outline strict inclusion and exclusion criteria for the studies they reviewed. They did not present a bias assessment of included studies. They did not include a table describing each of the included studies’ design, specific vaccine, participant population, study size, methods, and findings. Table 1’s questions for data extraction are not precise enough to inform a rigorous summation of their findings. In addition, they ranked the reasons for vaccine hesitancy according to the number of articles that cited the reason; the number of articles does not necessarily equate to evidence quality. By not following established systematic review methods,⁵ the validity of their results is questionable.

As we weather the first great pandemic of the 21st century, best practices to encourage vaccination are more important than ever. If the authors had chosen to follow established systematic review guidelines, readers might be more willing to implement their article’s recommendations. Conducting a lengthy cohort study of patients with varied vaccination status, as the authors recommend, could also delay needed change. The Centers for Disease Control and Prevention, the American Academy of Family Physicians, and the American Academy of Pediatrics⁶ instead encourage clinicians to use quality improvement to increase immunization rates. Quality improvement initiatives can more quickly lead to necessary change to achieve health equity in vaccination.