With the onset of the 2019 coronavirus (COVID-19) pandemic outbreak, caused by the severe respiratory coronavirus 2 (SARS-CoV-2) syndrome, the world entered a state of social constraints that limited social activities. and economic normalization covering broad spectrum, along with acute and often acute disease and death toll.
New study, released on the medRxiv* preprint server, examining the impact of a new variant of this virus on the epidemic course within the UK.
Lockdown, weather and viral spread
As vaccines are being distributed in many countries around the world, the emergence of new variables with increased transmission and violence, and part of an attack, at least, to centralized immunity, is of great concern. among public health authorities and inspectors alike.
Non-pharmacological interventions (NPIs) – such as wearing face masks, social distance and locks – were the only methods available for most of the pandemic, since intensive research of novel or reconstructed antivirals that focused, safe, and effective against the virus failed. In fact, h NPIs have reduced the spread of the virus, although there were still several continuous waves.
The status of locking tensions was closely monitored, and the economic policies implemented by the Oxford University Government Response regulator, for almost all countries, helped to understand the effectiveness of the lockout. those strategies.
Many studies show that the spread of the virus is higher in cold weather, while humidity appears to be reduced. The researchers in the current study followed an earlier paper, using both locking data and weather charts to predict viral spread in the form of the breeding rate.
The changing course and the UK pandemic
Many papers have also reported on viral classification. In fact, this pandemic marks the first time that rapid genomic sequences have been used at such a large scale. The UK will lead in this effort, through the COG-UK consortium.
As a result, the UK recognized version B.1.1.7, or 20I / 501Y.V1 or ‘UK’ or ‘Kent’ in the latter half of September, 2020. Following the publication of the series in October, it was then found spreading, albeit slowly, across the crowd.
At the moment, this has been a major difference in the UK, having been cited as a source of concern by Public Health England in mid-December.
This variability is marked by numerous spike mutations, raising fears against vaccination. However, preliminary data in the world show that the efficacy of a vaccine against a typical infection with this difference is around 74% with the Oxford / AstraZeneca vaccine. This is lower than the 85% protection against the previous differences.
A few cases have shown the presence of an additional E484K mutation, which may counteract this difference with natural and vaccine antibodies. Mortality rates with B.1.1.7 are 35% higher than the wildtype virus, says the UK’s Scientific Advisory Group for Emergencies (SAGE). At the same time, it is 70% more mobile than the original.
The current study aimed to understand how the Kent variant shaped the subsequent course of the UK pandemic.
What were the results?
The researchers argued that, of the three factors, the lock was more related to the virus’ reproduction number. The nearest association was at 12 days, agreeing with the incubation period of 6 days, and a median period of 7 days from the earliest symptom to death.
Humidity was associated with increased viral spread, peaking at 20 days. This may be due to a slight delayed spread by fomites. Interestingly, a positive correlation was not found in many other studies, with other patterns reported, possibly due to diffuse salts within the respiratory droplets.
Warmer weather reduces viral transmission, agreeing with known inactivation of the virus at higher temperatures, as well as shorter life of respiratory droplets under such conditions.
Prediction remains absent in the new variant
As a result of the current modeling approach cumulative death was expected to occur very close to actual mortality on that date. He also made a close estimate of the highest daily death, with the date off only five days.
The researchers estimated that last population immunity was around 32%, although only 25% of people were considered seropositive in the 28 days before February 11, 2021. In fact, this does not description of cellular immune responses to the virus.
Immunity prediction is important in this model and is calculated from the cumulative mortality, associated with a mortality rate of 0.5%. If natural immunity is not implemented in this model, the number of deaths would be expected at 7,00, 000, with 140 million diseases – affecting the UK population!
Instead, the predictions follow an older model that used only temperature and humidity, along with the harshness of locking down and the expected immunity. The viral rate is expected to remain unchanged despite the emergence of a UK variable.
Move in a line of control
In the real world, this VOC has become the dominant one, with higher transmission (and higher lifespan), showing a strong selection advantage. This may be due to the fact that the virus is known to change during an infectious disease. Patients with more severe illnesses and a higher chance of death may have had less strong immune systems and a higher viral load.
These patients would then be more likely to provide conditions in which the virus could adapt and grow into the new snout. Thus, such individuals would have been infected with the RA difference despite being infected with an old one.
The current interest in new and novel mutations may not account for the constant change and movement that has occurred since the virus first appeared in humans. This is related to the immune response and the ability to change the virus. Immunity can not be considered in binary fashion, as ‘Present’ or ‘Absent’, but as one point in the field of immunity to the old and new changes.
Variations associated with immune deficiencies may reduce viral infections, but this may be reduced by showing more mutations in this setting. More recent changes may therefore appear more contagious as individuals gain greater protection from an older version.
Again, the administrator of the locking strategies used here may not have included unofficial strategies, such as the personal locking that many people applied while discovering that a more contagious and perhaps more brutal variant has been released.
This may also contribute to the discrepancy between the actual and projected results in this study.
True vs. locking wire required
The study also notes the delay in locking effects, which means “It is easier to prevent the roof from tightening by early tightening than to smooth it with slower steps.. ”
The researchers estimate that three weeks of locking at an effective reproduction number of 0.86 would be required to see the one-week induced growth at R0 of 1.65, at the low levels of immunity that were common at times of the first and second locks.
As the virus affects more and more of the population, its endemicity can only be prevented by vaccination, which can provide great immunity within a short period of time to cut short the epidemic .
What is the conclusion?
The overall course of Covid-19 pandemic disease in the United Kingdom did not appear to have changed significantly when the Kent variant of the disease emerged, despite its selective advantage over strong strains. before. ”
Instead, it seems to be correctly predicted by lockout wiring and climate conditions, as it was before.
* Important message
medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be seen as final, guiding health-related clinical practice / behavior, or treated as fixed information.