Washington, Sep 1 : The nationwide Covid hospitalisations in the US have increased by nearly 19 per cent in a single week and deaths by more than 21 per cent, as the country goes through a late-summer spike in Covid infections. According to the latest Centers for Disease Control and Prevention (CDC) data, up to 10,000 people a week have been hospitalised with Covid, reports NPR. The rising Covid cases have prompted some schools, hospitals and businesses to encourage, or even require, people to start masking up again. CDC Director Mandy Cohen cautioned that Covid remains risky for people who are unvaccinated. The risk is especially high for unvaccinated individuals who haven't gotten the virus before and those who are older or have underlying health conditions. "About 70 per cent of hospitalisations are among those who are 65 and older," she was quoted as saying in the report late on Thursday. The health officials are watching two new variants -- Omicron variant EG.5 (Eris) which is dominant in the US and BA.2.86 which is starting to spread. The CDC warned last week that BA.2.86 may be "more capable of causing infection" in people who have previously had the Covid virus or vaccines. "All of that has driven some institutions around the country to reinstitute mask mandates, at least temporarily," said the report. The World Health Organisation (WHO) has designated EG.5 or Eris as a "variant of interest" as cases rise globally. "EG.5 is a descendent lineage of XBB.1.9.2, which has the same spike amino acid profile as XBB.1.5. EG.5 was first reported on February 17, 2023, and designated as a variant under monitoring (VUM) on July 19, 2023. With this risk evaluation, we are designating EG.5 and its sub-lineages as a variant of interest (VOI)," according to the WHO. According to WHO, the largest portion of EG.5 sequences are from China (30.6 per cent, 2247 sequences). However, it believes the variant does not pose a significant risk. /IANS