The breakneck speed at which vaccines have been produced to protect against Covid-19 and the new technologies being used have caused understandable concern about safety. There is a measure of unease among some people in Hong Kong about the drug produced by Pfizer-BioNTech, which an advisory panel has recommended for approval for an immunisation programme that could start in the latter half of next month. Reports of about 30 deaths in Norway and 10 in Germany and severe adverse reactions after injections elsewhere have grabbed attention. But while events need to be closely monitored and quickly responded to, only when risks are conclusively proven to outweigh benefits is alarm justified. Investigations are under way into the deaths, which involved elderly people who were frail and in poor health, many living in nursing homes. Norwegian and German medical officials have so far seen no need to revise guidelines for administering vaccines. Cases in Britain and the United States of what appear to be severe allergic reactions have prompted recommendations that patients with certain existing conditions be excluded and those given jabs be closely monitored. Pfizer’s trials did not find serious adverse events, although many participants experienced a range of reactions including fever, aches, nausea and diarrhoea. The Pfizer-BioNTech vaccine is among the most efficacious so far developed and coupled with its pharmaceutical pedigree, is a popular choice among governments. Hong Kong has included it among three candidates for a free immunisation scheme and it is the first to become available for distribution, with elderly residents and staff of care homes recommended to be prioritised for jabs. Hong Kong Covid-19 panel backs Pfizer vaccine, seeks more Norway deaths details Vaccines are in high demand and chances cannot be taken with supplies, so the health secretary should waste no time in taking the advice of experts and giving the go-ahead. Any immunisation scheme needs a carefully considered strategy. Advisers have mapped out a schedule for groups in society to be vaccinated, from most to least vulnerable. But there has to be flexibility, some jabs needing to be given on a case-by-case basis taking into account pre-existing conditions and matters like frailty. Roll-outs elsewhere must be closely monitored for problems.