London, Sep 19 : As Pirola, the new mutation of Omicron strain of Covid-19, worries health experts, the UK's National Health Service (NHS) has asked senior citizens above age 65 to immediately get their top-up booster jabs. People aged 65 and over in England are being urged to get a top-up booster vaccine against Covid at a time when more people are coming into hospitals with the highly-mutated BA.2.86 virus, reports the BBC. The vaccines will soon be provided for free to more vulnerable groups. "Hundreds of thousands of adults who are eligible for winter vaccines -- including all aged 65 and over, pregnant women and those with an underlying health condition -- will also begin receiving invitations from the NHS to encourage them to get their Covid and flu jabs from this week," NHS said in a statement late on Monday. According to the report, Covid hospital admissions are now at the highest rate since the end of April, at 4.6 per 100,000 people. That is still below the level reached last winter. The hospital admission rates remain highest among people aged 85 and over, followed by 75 to 84-year-olds. "Vaccines are our best protection against flu and Covid-19, and I strongly encourage all eligible people to come forward for their life-saving winter vaccines as soon as they can," Steve Russell, NHS director for vaccinations and screening, was quoted as saying. The UK Health Security Agency (HSA) last week reported 34 cases of BA.2.86, 28 of which were reported from a single elderly care home in Norfolk -- an early indicator that the variant may be sufficiently transmissible to have impact in close contact settings. /IANS