Researchers have warned that early rest in the 2019 coronavirus infection control measures (COVID-19) in the UK could lead to clear waves of additional diseases with the causative agent of true respiratory coronavirus syndrome 2 (SARS-CoV). -2).
The team’s mathematical model showed that even when phase 1 of the routine vaccination program is completed, strict non-pharmacological interventions (NPIs) will still be needed to prevent a major wave of disease if herd immunity has not been improved. establishment.
While the novel vaccines against SARS-CoV-2 provide a potential solution for counteracting the COVID-19 revolution, this largely depends on its potency. immunization to prevent transmission and uptake among the population. These factors need to be closely monitored as vaccination programs are distributed across the UK and other countries, warn researchers.
Matt Keeling and his colleagues from the University of Warwick found that even a gradual respite of NPIs over several months would not prevent the worst effects.
A pre-printed version of the paper is available on the medRxiv * server, while the article is subject to peer review.
First and second wave in the UK
In the UK, the first cases of SARS-CoV-2 were identified on 31st January 2020, with exponential increases in cases observed through February and March.
The government introduced the first national lock on 23rd March, which led to a decline in the infection rate that lasted until August. A subsequent break from control measures led to social interaction and mixing that led to a second wave and, finally, a second lockout in November.
In early December, the UK had more than 60,000 deaths and around 225,000 hospital admissions due to COVID-19.
Large-scale vaccination against SARS-CoV-2 represents a potentially very rapid exit strategy.
In early December 2020, developed one of the world’s first coronavirus vaccines (Bf162b2 Pfizer / BioNTech[6]) was approved for use in the UK, with several others showing promising results in end of Phase 3 tests.
Ro na 12th By December 2020, the UK had ordered 357 million doses of vaccines from seven different developers.
Expected daily deaths in the UK following the start of a vaccination and respite program or removal of NPIs. Panels (a) and (b) show the effect of resting on normal NPI measures down to those seen in early September 2020 (R 1.2 – 1.4) from January or April 2021 respectively. Panel (c) shows the total effects of partial release of NPI measures at different dates during the vaccination program (left) compared to total release from July 2021 (right); the upper limit, the middle bar and the lower of each box correspond to depressing, fundamental and optimistic assumptions about vaccine uptake. The lower panels (d) and (e) correspond to a gradual decrease in NPIs until the controls disappear, as seen in the gray area. The basic position (a, b, d & e) assumes 75% acceptance in the general population; the optimistic position is accepted at 85% in those over 50; although the depressing situation has resulted in a 65% reduction in people over 50 and 45% in the remaining population.
The dinamics of the vaccine against SARS-CoV-2 are complex
“Relatively simple relationships between epidemiological parameters, vaccine efficacy and vaccine uptake typically predict the success of any vaccination program,” says Keeling and colleagues.
“However, the dinamics of the vaccine against SARS-CoV-2 are complicated by age-dependent factors, variable disease rates and possible rest in non-invasive interventions. pharmaceuticals (NPIs) as the perceived risk decreases. ”
In particular, one factor is not known to what extent the novel SARS-CoV-2 vaccines inhibit further transmission.
What did the researchers do?
The team used a mathematical model with an age structure matched to a range of epidemiological data to predict the dynamics of COVID-19 into 2021 and beyond, based on a combination of scenarios. The model predicts the probable number of deaths and hospitals, thus providing an important insight into the interaction between the UK vaccination program and future rest or removal of NPIs.
Not surprisingly, the team found that the largest wave of diseases and the highest number of deaths occurred without vaccines.
With some rest on NPIs (to some extent in early September 2020) in early 2021, waves of infection occurred thereafter, even under the most effective assumptions (vaccines that block 75% of diseases).
The model estimated that more than 10,000 deaths would occur due to a slow decline in cases from the current high level of infection.
He also predicted that if all NPIs were fully built once both phases of the vaccination program were completed, there would be a major explosion and a large number of associated deaths.
When vaccines that did not inhibit transmission were considered, the removal of NPIs caused an unregulated wave of diseases that could only be removed by people who had successfully vaccinated.
The team says that even under optimistic assumptions for both vaccinations and uptake, the removal of NPIs could lead to 49,000 deaths, with 13,000 occurring between January and July and 36,000 from July onwards.
Slow rest of NPIs created the lowest number of deaths, which, under the most optimistic assumptions was still estimated at around 39,000.
What is the impact of the study?
The team says the study suggests that NPIs may be at rest before adequate flock immunity is applied to a major wave of diseases, hospitals and deaths.
Even with high levels of vaccination, a significant proportion of the population needs to be vaccinated to prevent future waves of infection. Strong NPIs will still be required, even when phase 1 of the vaccination program is complete.
“While the novel vaccines against SARS-CoV-2 offer a potential exit strategy for this revolution, this is largely dependent on the prevention action of transmission. vaccination and population uptake, and both must be closely monitored as vaccine programs are distributed in the UK and in other countries, ”concludes Keeling and colleagues.
* Important message
medRxiv publish preliminary scientific reports that are not peer-reviewed and, therefore, should not be seen as final, guiding health-related clinical practice / behavior, or be treated as information established.