Can the spread of COVID-19 infection be mitigated by a rigorous vaccination strategy within 100 days?

The worldwide outbreak of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) caused a pandemic of Coronavirus Disease 2019 (COVID-19). As of August 25, 2021, SARS-CoV-2 has infected more than 214 million people and killed more than 4.4 million people worldwide. Some COVID-19 vaccines have an Emergency Use Authorization (EUA) from various global regulators and can initiate vaccination programs in many countries around the world.

Despite these efforts, the emergence of SARS-CoV-2 mutants is threatened. Effectiveness of Vaccines because some mutants can escape the host’s immune response. However, scientists have found that the vaccines available are to varying degrees effective against all circulating SARS-CoV-2 mutants.

study: Can a vaccine-led approach end the outbreak in New South Wales in 100 days, or at least significantly reduce morbidity and mortality? Image Credit: pumpyvector / Shutterstock.com

Zero community infection of COVID-19 in Australia

Australia’s new policy goal is “zero community” Send COVID-19.. To achieve this goal, an early and serious blockade is being implemented shortly after the outbreak of the new COVID-19. Researchers believe that these efforts will ensure the rapid elimination of the virus from the community.

Since June 16, 2020, the number of cases of COVID-19 has skyrocketed in New South Wales (NSW). As of early August, an average of 300 cases were reported daily, an increase of 4% per day compared to the previous two weeks.

Unlike many states and cities that implemented immediate Stage 4 style blockades, the Government of New South Wales did not implement such a strategy. Instead, the government followed different restrictions based on the intensity of geographically different COVID-19 cases. To this end, the first state-wide blockade took place on August 14, 2021, accompanied by increased vaccination coverage.

During the latest blockade, the Government of New South Wales instead prioritized young and important workers for vaccination. Although the government hopes to relax these restrictions in August. 28, 2021; However, by that time, most individuals under the age of 40 have not yet been vaccinated.

New research

New research published in medRxiv * The preprint server evaluates the new COVID-19 policy implemented in NSW. Researchers in this study estimated a timeline to reach less than 5 COVID-19 cases per day under 12 combinations of 3 different blockade strengths, including weak, moderate, and strong. I made it a purpose.

These predictions also included four vaccination deployment settings. These include (a) prioritizing Pfizer’s mandatory workers according to the original vaccination plan, (c) rapid vaccination of 25% of AstraZeneca (AZ25) adults under the age of 60, and (D) Includes rapid vaccination. 50% of adults under the age of 60 in AstraZeneca (AZ50). Another purpose of this study was to predict the number of cases of COVID-19 and the hospitalization and mortality rates 100 days after August 1, 2021, according to the scenario described above.

The authors of this study used an agent-based model to analyze the status of NSWCOVID-19, including the circulation of delta variants. They argued that the study focused primarily on predicting possible patterns of infection throughout the community, rather than predicting the exact number of cases, hospitalizations, and deaths. .. The latter was reported by a scenario with wide intervals of uncertainty.

In this study, researchers used Monte Carlo simulations that took into account stochastic uncertainties and input uncertainties such as vaccine efficacy.

Investigation result

The current study estimates that 50% of individuals over the age of 16 will be vaccinated by October 10, 2021, according to the original vaccination plan. By comparison, 70% and 80% of this patient population is expected to be vaccinated by November 21st. December 28th of this year, respectively. This timeline has been shortened to October 1, October 30, and November 28 for the fastest (AZ50) rollout.

In addition, this study is the fastest approach for strong blockade with rapid vaccination to reach less than 5 COVID-19 cases per day with a median of 78 days by October 18, 2021. Clarified that there is a possibility. The vaccination rate will reach the target within 207 days or by February 24, 2022.

Interestingly, this study found that increasing blockade strength had a greater effect than increasing vaccination coverage. Researchers have shown that in the AZ25 vaccination scenario, 1,440 COVID-19 cases were reported under weak blockade, compared to 71 cases under strong blockade.

A heatmap of cases for the first 100 days of each strategy (or cases are first achieved less than 5 per day). Since hospitalization and death are infections for the first 100 days, the total number of hospitalizations is more than 100 days and up to (about) 10 days due to the time lag, and death is 2-3 weeks after infection considering the time lag. .. BAU: Deployment of vaccines according to national plans. INT: Shifts all Pfizers to key workers as a priority and then back to BAU. AZ_25: Prioritize essential workers like INT and immunize 25% of adults under the age of 60 with AstraZeneca. AZ_50: Increased to 50% of adults under the age of 60 vaccinated with AstraZeneca.

Conclusion

The authors of this study predict that 70% of individuals over the age of 16 living in New South Wales will need to be vaccinated to reach the goal of less than 5 COVID-19 cases per day. bottom. Rapid vaccination rates are important to protect the population from COVID-19 infections, especially after the border has been opened for tourism. In the coming months, the strength of the blockade will play an important role in reducing COVID-19 hospitalization and mortality.

Based on observations from previous modeling studies and current results, strict containment measures such as stage 4 restrictions could significantly reduce the number of COVID-19 cases. The new prediction also includes a Delta variant, which is more toxic than the original SARS-CoV-2 strain.

In conclusion, the authors emphasize the effectiveness of strong public health and social restrictions in reducing COVID-19 cases and hospitalizations compared to relying solely on increased vaccine deployment.

*Important Notices

medRxiv Publish preliminary scientific reports that should not be considered definitive as they are not peer-reviewed, guide clinical practice / health-related behaviors, and should not be treated as established information.