Health officials are warning of a possible second wave of norovirus this winter, as individuals who have already been infected may be susceptible to catching the bug again. This warning comes as a result of a shift in the dominant strains of the virus.
The UK Health Security Agency (UKHSA) monitors laboratory reports of norovirus and has noted that immunity to one strain does not guarantee protection against others. Data reveals a recent surge in cases of the GII.17 genotype, although its prevalence has decreased from 76% in November to the current 59%. Concurrently, the GII.4 strain has risen sharply, now accounting for 29% of cases, up from just 10% three months ago.
