Tens of millions of asylum seekers, migrants, refugees and internally displaced people around the world have been excluded from national Covid-19 vaccination programmes, according to World Health Organization research seen by the Guardian. The gaps mean that a scattered group numbering at least 46 million people, about the size of the population of Spain, may struggle to get vaccinated even if a global shortage of doses eases. Among the excluded are 5.6 million people internally displaced by six decades of civil war in Colombia, hundreds of thousands of refugees in Kenya and Syria and nearly 5 million migrants in Ukraine. India, Nigeria and Indonesia are among several large countries whose vaccination programmes exclude displaced people, according to the WHO’s review, which was conducted in March. Others, such as Pakistan, appear in the list but have since amended their plans to make them more inclusive. International health groups have been considering the problem of excluded populations for months, and the groups behind the vaccine-sharing facility Covax approved the establishment in March of a channel of doses reserved as a source of last resort for the most vulnerable people in communities with no other pathway to a jab. The channel, called the “humanitarian buffer”, will draw on 5% of the doses allocated to poor and lower-middle income countries through Covax, redirecting them toward the most vulnerable 20% in excluded communities, to be administered by NGOs such as Médecins Sans Frontières. Covax has estimated a maximum of about 33 million people would be eligible for vaccines from the buffer, accounting for the most at risk within these groups – health workers, older people and those with risky co-morbidities. It is unclear when, if ever, others in these excluded communities will be vaccinated and from what source. Humanitarian groups have said that even if all migrants, refugees and other vulnerable populations were included in national plans, there would still be between 60 and 80 million people living in rebel-held territories around the world who would be out of reach. The WHO research illustrates the scale of the gaps within government schemes. More than 70% of the 104 vaccination plans reviewed excluded migrants, leaving out more than 30 million around the world, including 4.9 million people in India and 2.6 million in the Ivory Coast. Nor did the majority of plans studied include refugees and asylum seekers, stranding nearly 5 million people without a shot, including 1.8 million in Colombia, 590,000 in Syria and 489,000 in Kenya. About 11.8 million internally displaced people were also omitted from most plans, leaving out 2.7 million Nigerians and more than a million Indians, according to the research. Public health experts have argued that exclusionary vaccine plans are ultimately self-defeating, leaving large pockets of the population unprotected and still able to contract and transmit the virus, including variants that may have the potential to evade the immunity granted by vaccines. “As we learned from the outset of Covid-19 and all the restrictions put in place, availability of testing and access to healthcare for coronavirus, no one is safe until everyone is safe, and that is absolutely the same for vaccination programmes,” said Nadia Hardman, a researcher in refugee and migrant rights at Human Rights Watch. “What we’re seeing in India now, and what we saw in the UK, is the development of variants which rely and depend on a community not being immune, and the extent to which vaccinations are rolled out to all in a territory is critical for the containment of the virus and containment of threatening variants.” Vaccine distribution tends to illuminate a state’s blind spots, and even some governments that putatively included refugees in their plans were doing too little to make sure they were actually vaccinated, Hardman said. She gave the example of Lebanon, which has included the 1.5 million refugees who make up a third of its population in its national plan, “but what we’ve seen is extremely low take-up rates and an unwillingness by authorities to put forward the kinds of promises and assurances and mechanisms to get refugees and vulnerable groups to vaccination centres”, she said. Countries can also apply to access Covax’s humanitarian buffer in extraordinary circumstances, such as the inflow of a large population of refugees. There is also a separate “contingency provision”, drawing from the same emergency stockpile, which allows countries to apply for an immediate surge of extra doses through Covax in case of an extraordinary outbreak, potentially such as that which India has experienced over past weeks. A spokesperson for the WHO did not comment on how many of countries named in the research had subsequently addressed the gaps in their vaccination programmes, but said: “Experience shows that despite best efforts, at-risk populations in humanitarian settings are often left behind and are at risk of being missed by government-led vaccination activities.”