Vaccine safety

Sometimes it is worth stating the obvious: ‘The development of safe and highly effective vaccines during the latter half of the 20th century has been one of medicine's greatest achievements … Collectively, traditional vaccines are estimated to save approximately 4–5 million lives per year’ (Malhotra, 2022).

But mistakes can be made in any field of human endeavour, including vaccine development. For example, in 1953 the first human pilot studies of a formalin-inactivated poliovirus vaccine were undertaken; and 1954 saw 1.8 million children in the US, Canada and Finland receive this vaccine in the world's largest clinical trial. However, in 1955, after mass polio vaccination began in the US, 250 cases of atypical paralytic poliomyelitis occurred after the Cutter and Wyeth pharmaceutical companies each released polio vaccine that had been inadequately inactivated (Juskewitch et al, 2010).

More recently, in 2015, the Philippine Food and Drug Administration approved Dengvaxia, an attenuated yellow fever virus that expresses genes of each of the four types of dengue virus; in 2017 the vaccine was withdrawn because of safety concerns over vaccine-induced enhancement; and in September 2018 it was revealed that 130 vaccinated children had died (Arkin, 2019).