The COVID-19 pandemic has had a profound impact on the lives of people and the global economy, along with devastating social and psychological consequences as a result of the recurrent lockout conditions. Recently launched COVID-19 vaccination programs are intended to prevent deaths and reduce congestion in hospitals to prevent the collapse of health care systems. As many infectious people develop serious disease and damage long-term symptoms, it is a priority to limit the cumulative number of cases.
Another key aim of the vaccine is to allow businesses, schools and public places to reopen safely. Prior to the implementation of the vaccine, a number of strategies such as mask use, testing and detection, and social distance were in place to prevent an increase in cases and subsequent closure. While these measures helped control the spread of the virus, they were not enough to prevent the recurrence of infectious waves in many countries.
Another key concern is the emergence of more contagious variants of the virus in many countries such as the UK, Brazil and South Africa. The UK or B.1.1.7 variant is believed to be significantly more contagious and is spreading across health care systems in the UK as well as spreading across the globe.
While the impact of non-pharmacological interventions on new SARS-CoV-2 modifications is not yet clear, these interventions come at a significant cost. School and business closures are disproportionately affecting people of color and socioeconomic backward areas. The main goal of vaccination plans should be to limit the intensity and length of locks this year.
Exploring the complexity of vaccine implementation using mathematical models
Recently, researchers from France and the USA analyzed the complexity of vaccine implementation during the 3rd a wave of SARS-CoV-2 diseases and potential future waves, using a mathematical model calibrated to data from King County, Washington. The aim of the researchers was to understand which variables have the greatest impact on disease and mortality to help limit them while reducing locked-in time. The review is published on the preprint server medRxiv*.
The model used by the team allows projections in other states with a lower or higher frequency at the start time of local vaccination programs. The researchers considered different scenarios with different vaccine levels, vaccine efficacy profiles, and case thresholds for implementing and participating in lockouts and assuming that variability is currently more contagious at different levels. mild.
“Our model projects that, with the new changes being more contagious, higher levels of partial diseases will lead to greater numbers of total diseases and deaths per person.”
A high vaccination rate and a low case threshold for promoting partial lockout are the main variables for limiting overall disease and mortality regardless of vaccine efficacy profile. Heat maps showing vaccine level (x-axis) coefficients and a case threshold for inducing partial (y-axis) locking are shown for four plausible vaccine profiles. a. VESUSC = 90% / VESYMP = 10% / VEINF = 10%, b. VESUSC = 50% / VESYMP = 10% / VEINF = 10%, c. VESUSC = 10% / VESYMP = 90% / VEINF = 10%, d. VESUSC = 10% / VESYMP = 50% / VEINF = 10%. The results are total infections (upper tier), total deaths (middle tier) and partially locked days after vaccination initiation (bottom tier). An increase in vaccine levels reduces disease and death across all conditions. An increase in vaccination rate significantly reduces total lockout days, especially when the case threshold level for partial lockdown is low. Reducing case thresholds for promoting partial lockdown reduces overall disease and death but leads to a higher number of partially locked days in many cases. Decreases in VESUSC (a to b) lead to more diseases and deaths with little effect on locked-in time. A reduction in VESYMP (c to d) leads to more diseases and deaths with very little effect on locked-in time. VESUSC provides a significant reduction in disease but a small reduction in mortality compared to equivalent VESYMP (a to c and c to d).
An increase in vaccination rates will reduce the number of cases and deaths, and the number of lock-in days
In all cases, the new variant became the dominant feature in early summer. Current and future low case thresholds for partial locks in waves strongly predict lower numbers of diseases, hospitals and deaths in 2021. However, delays are expected when rising in new diseases associated with changes in areas with seroprevalence to a higher degree. . For all vaccine efficacy profiles considered in this study, increasing vaccine uptake reduces the number of diseases and deaths and the number of partially locked days.
“With the high effectiveness of vaccines against new, more contagious changes, and in particular the ability to prevent persistent transmission rather than just prevent symptoms, it could prevent thousands of diseases and save hundreds of lives. an King County. “
The researchers are projecting great uncertainty about the timing and intensity of future waves due to changing estimates of the variability of emerging variables, the effectiveness of vaccines against these new variables, vaccine rejection, and adherence to future SARS-CoV-2 masks and social masks. infection. Nonetheless, in all the plausible scenarios considered in this work, rapid vaccination and the implementation of early lock-in are the most important variables that will help save the most outbreaks. most of life.
“It is often said that vaccines do not save lives, vaccines do. Our modeling strongly reinforces this point.“
* Important message
medRxiv publish preliminary scientific reports that are not peer-reviewed and, therefore, should not be seen as final, guiding health-related clinical / behavioral practice, or be treated as information established.