The announcement of measures to relax detention in the United Kingdom, made Monday (22) by Prime Minister Boris Johnson, was greeted with caution by British scientists. For them, it is too early to draw definitive conclusions about the impact of vaccination, and the recent success of the disease control is also due to a decrease in mobility of almost 70%, compared to the beginning of the last year.
Evidence of the importance of childbirth is that the decline in new cases, hospitalizations and deaths has occurred for all groups of the population, not just those who received the vaccines. Recent figures have shown the impact of vaccination on severe cases of illness, but a comparison with Israel also indicates the impact of reduced mobility.
The Israeli campaign has already vaccinated more than 87% of the adult population. But with less stringent containment, infections in Israel have declined at a rate that is half that of the UK. There were about 650 new cases per 100,000 people in Israel in the second week of this year, a number that has dropped to 312 (about half). In the UK, where 27% received vaccines, the rate fell from 475 to 115 / 100,000 over the same period, down 75%.
Recently considered a success story, the UK however still has higher infection rates than other major European countries. In Germany, for example, even with a still nascent vaccination (6.2 / 100), the infection rate is half British (61 new cases / 100,000). Still under confinement, Germany does not intend to reopen until this index drops below 35/100 000.
British scientists fear that greater mobility will reduce the gains already made. “With any luck, it looks like we will escape the huge increase in cases announced in June and July (thanks to better vaccines than we thought). But that will leave us very relaxed and we will open our guard to vaccine resistant variants, which will bring another peak in September, ”said Martin Hibberd, professor of emerging infectious diseases at the London School of Hygiene and Tropical Medicine (LSHTM). .
The latest UK data, released on Wednesday, is good news but does not yet help to relax, says professor of applied statistics Kevin McConway at Open University. “It’s impossible to predict what will happen with the deaths, but if they maintained the current rate of reduction, we would still have over 100 deaths per week through June.”
He said he hoped that with the advance of vaccination, deaths would decline more quickly, “but it’s hard to be absolutely sure at this point.” Even if the effects of vaccination become clearer and stronger, there will be pressure in the opposite direction. as the blocking restrictions are removed, he said.
Boris has hinted at the possibility of freeing international travel from the end of May, which increases that risk, according to Linda Bauld, professor of public health at the University of Edinburgh. “Vaccination will be slow in many parts of the world and the importation of cases will pose a significant threat to any progress we make in the country,” she said.
The risk exists because Sars-Cov-2 is still adapting to its human host, as evidenced by the more contagious variants discovered in recent months, according to Professor Stephen Griffin of Leeds University School of Medicine.
“Although vaccines clearly strongly limit the most serious consequences of coronavirus infection, allowing the pathogen to continue to circulate presents a very real risk that more serious variants may emerge to avoid immunizers,” a- he declared. For Griffin, “it is reckless at best” to allow Sars-Cov-2 to continue to spread.
The professor maintains that there are already enough weapons to allow the easing of restrictions, including vaccines and the fact that the population is “attentive and vigilant”. “As the climate improves, our behavior will further limit the spread of the virus.” According to him, the weak point remains the system for tracking cases and contacts.
LSHTM’s Hibberd agrees. If the testing, tracking and isolation system is not strengthened to quickly locate and contain a peak after the summer, he said, more feedlots may be needed next winter.
Public health experts have also criticized the four preconditions announced by Boris when presenting his roadmap for the lack of definition in England: 1) that the vaccination program maintains its current good performance; 2) that vaccines reduce hospitalizations and deaths; 3) infection rates do not overburden hospitals and 4) risk assessment is not affected by new variations.
“These conditions are all vague,” said Peter English, communicable disease consultant and chairman of the Public Health Medicine Committee of the British Medical Association (BMA). Without details on how they will be monitored and the metrics used, it will be difficult to assess the suitability of the new openings, he said.
back from school
English considers the minimum dates announced by Boris for the start of each of the four relaxation stages to be “very optimistic”. “Perhaps to boost morale, improve public relations, or appeal to critics of the Conservative Party who are eager to reduce restrictions faster than recommended by government science and medical advisers,” he said.
One of the controversial steps, according to the consultant, is to reopen all schools at the same time, on March 8: “This will increase the transmission and the number of new cases”. In other countries, the reopening has been done gradually, from the youngest to the oldest. That would be a more cautious strategy, according to Michael Head, a global health researcher at the University of Southampton. “The children desperately need to go back to school, but the downside of full return is an acceleration of the contagion.”
According to BMA, the Association of Directors of Public Health and the Independent Group of Government Advisers (Sage), the ideal would not be to reopen all schools until the number of new cases drops below 10 per 100,000 inhabitants during the week. By then, relays and escalations must be adopted.
The consultant also defends the installation of carbon dioxide counters (which make it possible to estimate the accumulation of aerosols and potentially infectious respiratory droplets) in all classrooms. If the concentration reaches an insufficient level, the doors and windows would open and, at the limit, the rooms would be emptied.
Although he was personally pleased with the announcement of the detente – “It will be great to be able to go back to the movies” – virologist Julian Tang, professor at the University of Leicester, said it would be necessary to follow up. near the young population not yet vaccinated. “Even if they don’t need hospitalization, they can develop long-lasting complications from Covid-19, shifting the burden to other departments in the health system,” he said.
Tang notes that more than half of the British population is still susceptible to the coronavirus, “including those under 18, a common reservoir for seasonal respiratory viruses”, and this lack of herd immunity is at the root of pandemics viral. For this reason, he says, an interval of four to five weeks between each relaxation stage is essential.
“With over 4 million cases and 120,000 deaths, I hope we have learned that this virus and its various variants should be treated with respect and caution,” Tang said.
“We have to be careful. Recent data on the number of cases suggests that the decline of the epidemic may already be on the decline and, as a result, the rate of contagion is starting to increase. If this trend continues, we may have less room for maneuver over the next two months, ”said Paul Hunter, professor of medicine at the University of East Anglia.