Vaccinating the world against COVID-19: How many shots would it really take?!

Health workers and employees of Philippine General Hospital register for COVID-19 vaccination, expected to arrive this month, in Manila, Philippines. Photo taken on February 9, 2021. About 80% of manufacturing capacity of leading vaccine makers in the West, estimated at 4.4 billion doses this 2021, had been pre-booked for 15% of global population.

• Vaccinating at least 70% of the earth’s 7.8 billion inhabitants — and that too, with a double dose — presents an unprecedented public health challenge.
• At this level (70%), experts say the desired “herd immunity” may be achieved. But some experts now say the best-case scenario is to immunise up to 90% of the population.
• With a double-dose protocol (two vaccines from the same manufacturer administered a few weeks apart), that means at least 5.85 billion people need to be inoculated, equivalent to 11.6 billion vaccines.
• This does not include vaccinations that may be needed against new variants now making the rounds in several countries.