ISLAMABAD: How long will the efficacy of the COVID-19 vaccines last is an open question so far. “The safety of these vaccines is evident but their effective life in persons receiving them is yet to be ascertained,” eminent professor Dr Saeed Akhtar told The News, when contacted.Another specialist Dr Kaleem concurred with this view and said that we would learn with the passage of time whether periodic boosters would be required to keep persons being administered the vaccine safe from the...