Letters: The limitations of a Covid vaccine

Still distant

Sir: In James Forsyth’s analysis (‘Boris’s booster shot’, 14 November) he infers that a vaccine, if provided to the majority of the UK population, would deliver herd immunity from Covid-19, noting that ‘it seems increasingly probable that by the second half of next year, we will be emerging from this Covid nightmare’. I pray that he is right, though fear he may not be. In a recent Lancet editorial the view expressed was the exact opposite, as it notes that any vaccines are ‘unlikely’ to prevent transmission, though will reduce the severity of symptoms and likelihood of death. Critically, if transmission cannot be stopped via vaccine, in the absence of R being systematically below one, then Covid-19 will remain in circulation in society. Even in the event of a 90 per cent effective vaccine, this would presumably still have significant consequences. The editorial concludes: ‘Often it is difficult to offer solutions, but it is straightforward in this case: interventions that have been in use since early in the pandemic, most crucially physical distancing and hand hygiene, must continue indefinitely.’