A resurgence of Covid cases is under way across the UK, with infections in the over-70s at a record high, official figures have shown.
Based on random swab tests taken in the community, the Office for National Statistics (ONS) estimates that almost 5%, or 1,544,600 people, in England had Covid in the week ending 12 March, and 3.5% of people in the oldest age group. Infections also reached a record high in Scotland, with one in 14 testing positive.
The high prevalence among older people has prompted unease, after reports this week that vaccine immunity declines steeply in care home residents. It is six months since many people in this age group had their last vaccine dose.
â€œOlder age groups, especially people who have been isolating for so long, are now quite vulnerable even if they have kept up to date with their vaccines,â€ said Paul Hunter, a professor of medicine at the University of East Anglia.
The increase in infections is being driven by the more transmissible Omicron BA.2 variant, which has become the dominant strain across the UK. It transmits more readily than the original BA.1 strain but there is good cross-immunity between the two variants.
â€œItâ€™s basically sweeping up everyone who didnâ€™t get Omicron the first time around,â€ Hunter said. This, he added, meant the current wave was more likely to follow a short, sharp trajectory as had been seen in Denmark and the Netherlands, where there had been an Omicron BA.2 wave.
â€œIt wouldnâ€™t surprise me if it peaks before the end of March,â€ he said.
Prof James Naismith, a director at the Rosalind Franklin Institute at the University of Oxford, noted the higher prevalence in Scotland than England â€“ despite its more stringent rules, including a continued mask mandate in shops and on transport.
â€œThe reality is that differences in control measures between the countries are meaningless,â€ he said. â€œPrevalence is increasing in every area and across age groups. Without vaccines, this would be bleak .â€¦ Countries with poor vaccination rates face a very challenging future.
â€œFor the UK, my main concern is for the vulnerable, for whom this disease is serious and for those whose lives will be blighted by long Covid. Every effort must be made to triple-vaccinate as many people as possible, quadruple-vaccinate the most vulnerable and make available antivirals.â€
Sarah Crofts, the head of analytical outputs for the ONS Infection Survey, said: â€œThese latest figures show further increases in infections across most of the UK with high levels of infection everywhere, and in Scotland the highest our survey has seen.
â€œThese increases are largely driven by the marked rise of the Omicron BA.2 sub-variant,â€ she added. â€œItâ€™s notable also that infections have risen in all age groups, with the over-70s reaching their highest estimate since our survey began.â€