In big clinical trial experiments like the one Pfizer conducted to test its vaccine, not all volunteers are given the real shot. About half are given an inactive substance known as a placebo. In the Pfizer trial, half of the approximately 44,000 people who volunteered received a placebo shot. The other half received the vaccine which, after more than two months, proved to be 95 effective at preventing COVID-19.

Kwa maana Mungu aliupenda ulimwengu kiasi cha kumtoa Mwanae pekee, ili kila mtu amwaminiye asipotee, bali awe na uzima wa milele.