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Bellavite P, Donzelli A. Adverse events following measles-mumps-rubella-varicella vaccine: an independent perspective on Italian pharmacovigilance data. F1000Res. 2020;9:1176. Published 2020 Sep 28. doi:10.12688/f1000research.26523.2
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Revised. Amendments from Version 1
- About choosing among different formulations of vaccines, we have stressed that the parents’ informed consent requires a balanced and complete information and that the doctor's advice to hesitant parents is further complicated by any vaccination obligation. - A contribution to evaluate the short- and long-term benefits and risks of vaccines might come from comparative studies between vaccinated and unvaccinated groups of children. Some preliminary evidence from observational studies is provided, showing that in high-income countries the vaccinated children are not healthier than the unvaccinated ones. - We have suggested that an investigation on the possible “non-specific effects” of vaccines could be performed with properly designed and long-lasting randomized controlled trials, with experimental and control groups formed by children of correctly and thoroughly informed but still persistently hesitant parents.
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Peer Review Summary
| 2020 Dec 3 | James Lyons-Weiler | Version 1 | Approved |
| 2020 Nov 26 | Arthur Brawer | Version 1 | Approved |
Abstract
Vaccine surveillance programs are crucial for the analysis of the vaccine’s safety profile and the guidance of health policies. The Epidemiological Observatory of the Italian Apulia Region carried out an active surveillance program of adverse effects following immunization (AEFI) after the first dose of the measles-mumps-rubella-varicella (MMRV) vaccine, finding 462 AEFIs per 1000 doses, with 11% rated serious. Applying the World Health Organization (WHO) causality assessment algorithm, 38 serious AEFIs/1000 enrolled were classified as ‘consistent causal associations’ with MMRV immunization. Severe hyperpyrexia, neurological symptoms and gastrointestinal diseases occurred in 38, 20 and 15 cases/1000 enrolled, respectively. A projection of such AEFIs in an Italian birth cohort would give tens of thousands of serious AEFIs. These incidence data are much greater than the incidence of serious AEFIs reported by the Italian Medicines Agency (AIFA) for years 2017 and 2018, mainly based on passive (or mixed) pharmacovigilance. In a previous epidemiological study in the same Italian Region, during an eight year passive surveillance, the reporting rate of serious AEFI was 0.06/1000 doses, and no cases of febrile seizures were detected applying the WHO algorithm. Taken together, the data suggest that passive pharmacovigilance is utterly inadequate to document the real incidence of serious AEFIs and that current methods of assessing causality may be questioned. Active surveillance programs are required in representative population samples, with results presented separately from those of spontaneous reporting, and causality assessment should be performed carefully and using a correct technique for AEFIs presenting as complex and multifactorial diseases, like those with serious neurologic disorders.
Keywords: Measles-mumps-rubella-varicella vaccine, MMRV, Pharmacovigilance, Active surveillance, WHO Guidelines for causality assessment, Vaccine safety, Adverse events following immunisation, AEFI.
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