As the next phase of vaccine drive began for 18-45 age group recently, there are still doubts about the vaccine. In part two of our Vaccine FAQs series, Dr Jeenam Shah, a consultant pulmonologist with Saifee, Wockhardt and Bhatia Hospitals in Mumbai who has been treating Covid-19 patients since March last year, answers the most frequently asked questions—from 'how effective will the vaccine be on the ones who had contracted the virus in second wave' to 'should one wait for Pfizer of J&J vaccine'?