Governments have an ethical duty to take into account a list of factors in considering the vaccination modality they adopt, says a paper co-authored by Jonathan Wolff, Alfred Landecker Professor of Values and Public Policy and published in the British Medical Journal - Global Health.

Ethical and policy considerations for COVID-19 vaccination modalities: delayed second dose, fractional dose, mixed vaccines provides a framework for governments of countries which are considering administering COVID-19 vaccines in ways that have not been informed by clinical trials, nor recommended by the manufacturers or authoritative international health bodies (these include delaying the second dose of two-dose vaccines beyond the period for which there is evidence from clinical trials, or foregoing it entirely, giving fractional doses, providing vaccines for individuals outside recommended age ranges, or providing different vaccines for the first and second, or booster, doses).

In developing their policies, governments must take seriously the evolving scientific evidence base, as well as potential effects on public trust, the legitimate expectations and rights of those who have been begun the vaccination process, responsibility to the global community and equity. They also need to communicate their reasons for their decisions appropriately to the affected populations. Any decision to adopt a modality that differs from those recommended by manufacturers must be accompanied by comprehensive and clear mechanisms to follow-up those in alternative modalities.