critical to ensure people actually receive the vaccines. This requires multi-national

cooperation across many sectors to ensure that individuals in resource-limited

countries can access the vaccine and those who are vaccine-hesitant receive accu-

rate information. Incentive structures such as vaccine passports are already im-

plemented globally. Assuming that 70% of the global population needs to be

vaccinated to ensure herd immunity, it translates to 11 billion vaccine doses.

Further, in a situation where there is a sudden increase in demand for vaccines that

production cannot keep up with, fractional dosing might need to be implemented as

it has been for other outbreaks [56].

Many unknowns also exist. There is the issue of emerging variants and the

uncertainty as to whether the current vaccines will remain efficacious. Also, how

long will immunity last? Will annual booster doses be needed for the general public,

or only for those who are immunocompromised? Will annual booster doses be

needed against emerging variants? Many of these questions are currently being

investigated. However, these questions will surely soon be answered, because if

anything has been learned from this pandemic, it is the incredible feats that can be

attained when an urgent need meets global cooperation.

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