At the launch of the government’s “Living with Covid” strategy in February Chris Whitty, the chief medical officer for England, and Patrick Vallance, the chief scientific adviser, cautioned that the virus would continue to undergo marked evolution for at least a couple more years. In early May Christina Pagel, a consummate Covid watcher and professor of operational research at University College London, predicted that we were about six weeks away from the start of a new wave. With cases numbers and hospitalisations now rising again across the UK, both warnings are proving to have been prescient.
The nomenclature can be off-putting, but the gathering rise in infections is due to four offspring of the Omicron variant that dominated in the UK throughout the first half of 2022. In the winter and spring BA.1 then BA.2 spread through the country. Now their progeny BA.4, BA.5, BA.2.12.1 and BA.5.1 are vying to establish a summer wave. Whichever becomes dominant, all appear a notch more contagious than even their highly transmissible forebears. And whereas BA.1 and BA.2 had a predilection for the upper airways, resulting in generally milder disease, preliminary lab work on BA.4 and BA.5 suggests a greater affinity with lung tissue, harking back to earlier, more virulent variants such as Delta.
At its peak the BA.2 surge infected as many as one in 13 people in any week, causing widespread disruption to services and businesses due to staff absences. Hospitalisations rose significantly, though intensive care occupancy and death rates, while very far from trivial, were notably lower than in previous waves. In part this reflected the lower virulence mentioned above, but substantial population immunity from vaccination and prior infection, together with our expanded arsenal of effective treatments, will have played significant parts.
A number of factors suggest this new wave may be smaller than that caused by BA.2. Good weather means more outdoor mixing and better ventilation of indoor spaces, mitigating against transmission. And although both BA.4 and BA.5 appear to have a moderate ability to evade prior immunity from vaccination, we do have a high degree of population protection. The very elderly and the clinically vulnerable have recently been afforded a fourth vaccine booster dose. Most other people are many months out from their third dose, but the huge numbers of recent BA.2 infections may have created a comparable boosting effect. This is not the case, however, in unvaccinated individuals, or in those who had only an initial dose back in 2021. BA.1 and BA.2 infection alone appear not to induce natural immunity against the new strains taking hold. With vaccine uptake lowest among deprived groups, Covid continues to expose our nation’s scandalous socioeconomic inequality.
Whatever the height of this looming summer wave, we are not going to see a return of the mandated public health measures that so successfully averted the collapse of the health service during the first wave in spring 2020 and the Alpha (Kent) variant wave in early 2021. The economic costs of social restrictions, and the huge impacts on mental health and on care for non-Covid conditions, would far outweigh hospitalisation and death rates that are now comparable to a seasonal flu. But there are mitigations that a responsible government should be vigorously pursuing. Chief among these is enhanced ventilation or purification of air in crowded indoor spaces. This would reduce transmission of all airborne respiratory infections, and if adopted widely would transform our prospects for the winter to come and its inevitable further Covid wave.
For the government to take this seriously would involve a broadening of outlook away from the narrow mortality and hospital admissions data that have dominated discourse to date. According to the Office for National Statistics close to two million people, many of whom had mild initial infections, are experiencing long-term health impacts from Covid. Rates are highest in exposed professions: social and healthcare, and education. There is now incontrovertible scientific evidence that, for a substantial minority, Covid represents a chronic multisystem disease, capable of affecting virtually every organ in the body, from heart to brain, liver to lung. A failure to dampen the waves that continue to sweep the population will cause untold and, at present, officially unacknowledged, harm.