With no clear or agreed upon standard for a vaccine passport, vaccine inoculation rates vastly uneven and new variants of the virus threatening the progress already made in some nations, it’s unclear when Saudi Arabia will play host again to the millions more Muslim pilgrims it planned to receive in years to come.

Clinical research studies of the mRNA-based vaccines for children under 12 are ongoing, and authorization of a vaccine for this younger age group is still at least several months away. These trials are necessary because children have important differences in physiology and responses to vaccines from those of adults. Conducting separate studies in children under age 12 is a vital step toward ending the pandemic.