Covid-19 cases are increasing again in the UK, but the dynamics of this wave will be different because the majority of adults have been vaccinated.
Martin McKee was immediately convinced that a third wave of Covid-19 was imminent when the first data on the new Delta form of Sars-CoV-2 began to trickle in between April and early May.
McKee, a professor of European public health at the London School of Hygiene and Tropical Medicine, was particularly taken aback by estimates of Delta’s R number, the average number of persons infected by a single virus. “It was clear that this was a much more transmissible variant,” McKee explains. On June 16, Public Health England’s director of strategic Covid-19 response warned MPs that if the new strain is allowed to grow unchecked, its R number may be between five and seven.
McKee believed it was inevitable that new instances of Covid-19 – which had been dropping gradually since early January – will resume their upward trend. On June 24, the number of daily infections in the United Kingdom surpassed 16,000, a level not seen since early February, when the United Kingdom remained in complete lockdown.
However, the third wave will be markedly different from the previous two. While the Delta variety is regarded to be more virulent than any preceding version, the UK’s effective vaccination campaign appears to have broken the previously unbreakable relationship between infections, hospitalizations, and fatalities. Hospitalization rates are low at the moment. On June 22, 182 new hospital admissions occurred, representing a rate of 16 per 1000 new cases, compared to 3,812 admissions on January 12, the peak of the second wave, or an 84 per 1000 new case rate.
Boris Johnson’s government intends to lift all restrictions on July 19, although the exact impact on new cases of Covid-19 and public health is nearly difficult to predict, given the population’s different levels of immunity to the virus.
“The third wave will be distinct from the previous two, but the situation is too complex to model,” says Ravi Gupta, a University of Cambridge professor of clinical microbiology. “You have a large number of vaccinated people, those who are semi-immune as a result of previous infection, unvaccinated people, and a large number of young people.”
Additionally, intensive care units across the UK report a highly fragmented image, making it far more difficult for policymakers to formulate a coherent plan. While the third wave has already intensified in the North West, where 17,496 new cases have been reported in the previous seven days, transmission in other regions remains relatively low. “Everything is fine where we are,” says Matt Morgan, consultant in intensive care medicine at the University Hospital of Wales. “Wales is performing exceptionally well. However, in certain areas of the North and West Midlands, you can see this scooped-out curve of hospital population growth, which is cause for concern.”
Morgan believes that this regional variance is making it difficult for the public, already mentally exhausted from numerous lockdowns, to grasp the probable threat posed by the third wave. “Waves one and two were, to a degree, a case of ‘We are all in this together,’” he explains. “That is not the case anymore, and it is exceedingly difficult for people to grasp the narrative that the vaccination campaign has been so successful, but there is still an ongoing risk.”
While the NHS continues to vaccinate the public with remarkable efficiency – as of June 22, 64% of the population had gotten at least one dose of the vaccine — a proportion of the population remains unprotected. Martin Landray, a professor of medicine and epidemiology at the University of Oxford, notes that some older individuals will not develop a full immunological response to the vaccination, while others who received the vaccine in the early months of the campaign may experience some side effects.
Nadhim Zahawi, the Covid vaccine deployment minister, stated last week that nine out of 10 people eligible for a vaccine have accepted one. Landray notes, however, that this still leaves one-tenth of individuals eligible for vaccination unvaccinated. “Either they did not want it, did not show up, or were unable to have it due to a medical condition. Everyone believes that older age groups are covered, but we will continue to have issues with unvaccinated individuals,” he says.
Landray is concerned that if case numbers continue to rise, the virus could finally reach people at risk in the coming months, potentially resulting in another spike in hospitalizations. One issue is that individuals who have received all vaccines may still be capable of spreading the Delta version to a certain level. Gupta cites an Indian study of healthcare workers that found that even those who had received two vaccine doses contributed to transmission chains within hospitals, hence driving the epidemic.
McKee believes that the government should consider vaccination of teenagers as a method to mitigate the threat of the third wave on the elderly and vulnerable. “At the very least, this needs to happen,” McKee says. “While the Joint Committee on Vaccination and Immunization is primarily concerned with the risks and benefits to children, our countries have a long history of vaccinating people for the greater good. We vaccinate children against influenza in part to prevent them from contracting it, but mostly to prevent them from infecting their grandparents.”
Since the first wave of pandemics, a great deal has changed. Doctors now have a slew of new alternatives for combating the infection. Over the last year, the UK’s groundbreaking RECOVERY Trial – a program that began enrolling patients in March 2020 and will enroll tens of thousands of patients at dozens of hospitals for clinical trials investigating Covid-19 therapies – has provided critical information on which treatments work and which do not – has provided critical information on which treatments work and which do not. Morgan emphasizes the importance of the latter information, stating that it has aided in streamlining care routes on wards and in intensive care.
Convalescent plasma, hydroxychloroquine, aspirin, colchicine, and azithromycin have all been ruled out as a consequence. However, dexamethasone, tocilizumab, and monoclonal antibodies – which are synthetic antibodies that can be given intravenously to elderly or immunocompromised patients who are unable to establish an immune response against the virus – have been proved to be effective life-saving medicines.
Both dexamethasone and tocilizumab contribute to the dampening of the lethal cytokine storm that has been generally attributed to many of the Covid-19 fatalities. The latter treatment will be available beginning in December 2020, while several monoclonal antibody medicines were recently approved in response to fresh findings from the RECOVERY research.
At the same time, the information we now have about some of the virus’s longer-term consequences, particularly Long Covid, which has been particularly hard on younger, previously healthy women, means that the risk posed by the third wave cannot be quantified solely in terms of hospitalizations and deaths.
SarS-CoV-2 can persist in the brain as a chronic infection, causing structural alterations and increasing the risk of strokes, muscular difficulties, dementia, and psychiatric disorders, even in people who are not hospitalized.
Almost definitely, the third wave will appear somewhat different from the first two. There will undoubtedly be fatalities, but none like the magnitude experienced during the prior two rounds. As a result, some physicians believe that any decision to reinstate limits in the months ahead will likely be motivated by moral and ethical considerations rather than medical need.
“I believe that during wave one and wave two, it was clear that a massive emerging wave of infections, hospitalizations, and deaths was occurring,” Morgan adds. “Now, however, things are different. I believe that these are no longer medical judgments; they are ethical, moral, and sociological ones that must be addressed by society, governments, and ethical institutions.”