Travel bans and restrictions will not keep the Omicron variant of the covid out of national borders. And they also risk slowing down studies on the mutant. This is supported by several scientists in an article published online in ‘Nature’. More than 50 countries have stepped up border controls to slow the spread of the highly mutated new variant across South Africa. But the researchers say that many of the restrictions introduced, especially those aimed only at travelers from a handful of countries, are unlikely to keep Omicron out. These measures, on the other hand, have a significant cost for the countries concerned. In some of the affected areas, the voice of scholars has also been raised to warn of another ‘side effect’ of travel bans: the risk that urgent research on Omicron will be slowed down, limiting the arrival of imported laboratory supplies. Karen Grépin, a health economist at the University of Hong Kong who studies border control measures, is not “optimistic that the way these measures are implemented will have an impact right now”. “It’s too late. The variant is circulating globally,” agrees Kelley Lee, who studies global health at Simon Fraser University in Burnaby, Canada. Most of the travel bans are in South Africa, which has sounded the alarm. on Omicron on November 24, and Botswana, another country that reported the first cases of the variant. But many nations also stop visitors from neighboring Lesotho, Eswatini, Zimbabwe and Namibia. In South Africa’s most populous province, Gauteng, Omicron now accounts for most of the virus samples sequenced in recent weeks. But for the experts it is too late to stop the variant elsewhere as well, so much so that, Grépin observes, “as soon as the countries start looking for it, they find it, then the time advantage is probably gone”. Not only that: border restrictions could dissuade nations from alerting the world of future variants, the article highlights. This adds to the concrete impact that has already occurred: Few planes are now arriving in South Africa carrying cargo, including the laboratory supplies needed for sequencing. At a time when researchers are racing to understand Omicron’s transmissibility and eventual ability to evade the immunity created by vaccines, but also the severity of the disease caused. “The travel ban will paradoxically affect the speed at which scientists they are able to investigate, “says Shabir Madhi, a vaccinologist at the University of the Witwatersrand in Johannesburg, South Africa. There may also be difficulties in sharing samples with collaborators globally. “Within the next week, if nothing changes, we will run out of sequencing reagents,” adds Tulio de Oliveira, a bioinformatician at the University of KwaZulu-Natal in Durban, South Africa. Border control measures, it is finally pointed out, should certainly be used not alone, but in conjunction with efforts to strengthen public health interventions such as social distancing, the use of masks and vaccination, says Grépin, because Genomic studies have shown that cases will eventually escape the mesh of restrictions. Ultimately, the aim should be to buy countries the time to prepare their health systems for Omicron’s potential impact. But unless these countries implement internal measures, it is difficult to know what “we are buying time for,” concludes Catherine Worsnop, who studies international cooperation during global health emergencies at the University of Maryland in College Park.