Vaccine safety evaluation: Practical aspects in assessing benefits and risks

Abstract

Vaccines are different from most medicines in that they are administered to large and mostly healthy populations including infants and children, so there is a low tolerance for potential risks or side-effects. In addition, the long-term benefits of immunisation in reducing or eliminating infectious diseases may induce complacency due to the absence of cases. However, as demonstrated in recent measles outbreaks in Europe and United States, reappearance of the disease occurs as soon as vaccine coverage falls. Unfounded vaccine scares such as those associating the combined measles-mumps-rubella vaccine with autism, and whole-cell pertussis vaccines with encephalopathy, can also have massive impacts, resulting in reduced vaccine uptake and disease resurgence. The safety assessment of vaccines is exhaustive and continuous; beginning with non-clinical evaluation of their individual components in terms of purity, stability and sterility, continuing throughout the clinical development phase and entire duration of use of the vaccine; including post-approval. The breadth and depth of safety assessments conducted at multiple levels by a range of independent organizations increases confidence in the rigour with which any potential risks or side-effects are investigated and managed. Industry, regulatory agencies, academia, the medical community and the general public all play a role in monitoring vaccine safety. Within these stakeholder groups, the healthcare professional and vaccine provider have key roles in the prevention, identification, investigation and management of adverse events following immunisation (AEFI). Guidelines and algorithms aid in determining whether AEFI may have been caused by the vaccine, or whether it is coincidental to it. Healthcare providers are encouraged to rigorously investigate AEFIs and to report them via local reporting processes. The ultimate objective for all parties is to ensure vaccines have a favourable benefit-risk profile.

Towards the first multi-epitope recombinant vaccine against Crimean-Congo hemorrhagic fever virus: A computer-aided vaccine design approach

“…The amino acid residues of the vaccine, which are located in 126-141 region showed highest score (1.21 artificial infection and clinical disease, vaccine efficacy under natural disease conditions and the long-term efficacy are assessed. However, the vaccine development time, may be affected by some other parameters such as nature of target pathogen, equipment and facilities available, technical and manufacturing hurdles [65,66]. Therefore, determining the exact time to introduce a vaccine is very difficult; but using computational methods and in silico validations the required time can be reduced.…”

Post-marketing surveillance of adverse events following measles, mumps, rubella and varicella (MMRV) vaccine: retrospecive study in apulia region (ITALY), 2009-2017

“…Immunization is probably the most successful and cost-effective public health intervention; however, due to the advanced control of several vaccine preventable diseases, the topic of vaccine safety has become as important as the efficacy. 1 Adverse events following immunization (AEFIs) are medical occurrences following immunization, and they do not necessarily have a causal relationship with the vaccine. Adverse events may be unfavorable or unintended markings, an abnormal laboratory finding, a symptom or a disease: benefits of vaccines are significantly higher than the risks because AEFIs are absolutely rare.…”

Adverse Events Following Measles-Mumps-Rubella-Varicella Vaccination and the Case of Seizures: A Post Marketing Active Surveillance in Puglia Italian Region, 2017–2018

“…No drug, medical procedure or immunization can be described as totally risk free. A vaccine is a very particular type of drug because it is administered to a great number of people, in major part in good health, including infants and children, so there is a low tolerance for potential risks of adverse events, even if vaccines are held to a higher standard of control than other medical products [1][2][3][4][5].…”