Vaccination against human papillomavirus (HPV) has been progressively implemented in most developed countries for approximately 10 years. In order to increase the protection of the vaccines, a 9-valent vaccine (HPV9) was developed, which provides protection against nine types of the virus, but is not yet used in prevention programs. Studies evaluating its safety are rare. Thus, in this study we performed a meta-analysis of three clinical trials assessing adverse effects in women randomly vaccinated with HPV9 or tetravalent vaccine (HPV4), with the objective of analyzing whether the HPV9 is as safe as HPV4.
A systematic review and metaanalysis of the HPV vaccines' safety in women was made. Randomized controlled trials (RCT) published between 2011 and 2016 were identified from searches of PubMed, Embase, Scopus, Web of Science and the SciELO databases.
The studies selected 27,465 women who received one of the two vaccines. Results showed that pain (OR 1.72; 95% CI 1.62-1.82) and erythema (OR 1.29; 95% CI 1.21-1.36) occurred significantly more in HPV9 group. However, there was no significant difference between groups for the following adverse effects: headache (OR 1.07; 95% CI 0.99-1.15), dizziness (OR 1.09; 95% CI 0.93-1.27) and fatigue (OR 1.09; 95% CI 0.91-1.30) and the occurrence of serious events related to vaccination was similarly rare among those vaccinated.
Therefore, our findings demonstrate that HPV9 in female patients is as safe as the tetravalent vaccine.
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