Modeling shows that SARS-CoV-2 Omicron puts a serious burden on UK medical services

In a recent study published in medRxiv * Researchers, preprint servers, use UK data and mathematical models to determine the impact of the coronavirus 2 (SARS-CoV-2) omicron variant of severe acute respiratory syndrome on future infection risk. ..

study: Short-term forecasts based on early Omicron variant dynamics in the United Kingdom. Image Credit: CKA / Shutterstock.com

SARS-CoV-2 Omicron variant

Since the beginning of the 2019 coronavirus disease (COVID-19) pandemic, several different SARS-CoV-2 variants with enhanced immunological compatibility have emerged worldwide. The SARS-CoV-2 Omicron (B.1.1.529) variant was first reported in South Africa on November 24, 2021. Shortly thereafter, the World Health Organization (WHO) designated Omicron as a variant of concern (VOC).

Scope of testing in the UK that can identify S-Gene Target Failure (SGFT). In southwestern regions with low coverage, it is less likely that the Omicron and Delta variants can be quickly distinguished.

Currently, the number of cases of COVID-19 is increasing rapidly all over the world after the advent of Omicron. This is thought to be due to the higher transmission rate of this variant compared to other SARS-CoV-2 strains due to the more than 30 mutations in the spike (S) protein region. In addition to increasing their infectivity, these mutations also help evade the immunity that the Omicron mutant has acquired from existing vaccines and previous SARS-CoV-2 infections.

About research

In this study, researchers used SARS-CoV-2 data from the United Kingdom to perform sensitivity analysis and mathematical modeling to contagious, hospitalization, mortality, and future non-pharmaceutical interventions for Omicron variants. Predicted the impact of.

Early signs of Omicron infection were analyzed from case data from the UK HSA line list. Then, using the UKHSA linelist cases and reinfection data, and mathematical models previously developed by researchers, SARS-CoV-2 transmission dynamics within the United Kingdom’s seven National Health Service (NHS) regions. I simulated it. The authors included Omicron in previous models that included SARS-CoV-2 wild-type, alpha, and delta variants.

The BA.1 and BA.3 omicron substrains could not be amplified with the S gene target (SGTF), but the BA.2 substrains did not display SGTFs. Omicron progression was followed using a SARS-CoV-2 polymerase chain reaction (PCR) test at the British Lighthouse Institute using the TaqPath S gene target.

Participants in the model were divided into 21 age groups, with an age difference of 5 years. The model COVID-19 cases were the first infection (F) in the household, subsequent infections from symptomatic and asymptomatic household members (SI, SA), and the first subsequent detection in isolated households. It was classified as a case (QF, QS). .. The degree of vaccine protection against Omicron was determined by the Pfizer, Moderna, or AstraZeneca vaccinated person.

Investigation result

The results show that in early December 2021, the identified SGTFs were highest in northeastern England and lowest in southwestern England, while lab coverage was inconsistent in London.

From November 1, 2021 to December 13, 2021, cases of delta variant S gene-positive showed a slow decline, while cases of Omicron SGTF showed a rapid increase. However, since the beginning of December 2021, the growth rate of SGTF cases has decreased slightly due to delays in reporting and variability in the age distribution of SARS-CoV-2 cases.

With the advent of Omicron in early December 2021, reinfection rates surged in all age groups, especially adults aged 20-29 years. After stratification by age group and region in England, a rapid increase in reinfection of young adults was observed in all regions, including those with low SGTF coverage. In contrast, the modeled infections showed an even distribution of Omicron cases in individuals aged 25 to 44 years.

The estimated daily rate of reinfection cases in England is stratified by age group, showing a significant increase in December in many age groups and previously relatively constant in each age group. It exceeds the reinfection rate, indicating the invasion of Omicron. Observations are indicated by dots, fitted splines are indicated by lines, and 95% confidence intervals are indicated by shaded areas.

A comparison of SGTF cases from UKHSA data with Omicron cases in the study’s transmission model showed that the predicted rate of new infections was due to Omicron mutations.

Young adults are most susceptible to infection, convalescent immunity is predominantly observed in people under the age of 60, and the majority of individuals over the age of 60 are protected by booster immunization, according to a model that estimates the immunity distribution to Omicron. It was done.

Estimated distribution of immune status by age from the model in early December 2021. Sensitive people (unprotected, blue) are concentrated in the youngest age group, but those with immunity due to infection (green and recovery) are generally under 60 years of age. The majority of people over the age of 60 are protected by the booster vaccine (yellow).

Conclusion

In the current study, the author extended the existing SARS-CoV-2 prediction model to show the rapid relative growth of the Omicron variant compared to the Delta variant, including the dynamics of the Omicron variant in England. In addition, infections, hospitalizations, and mortality surged, followed by an increase in SGTF induced by Omicron. The findings will help predict future scenarios and the impact of various interventions associated with this new variant.

The TaqPath PCR test provided clear images of the relative growth of the Omicron variant, but the other measurements used in this study were significantly unsuccessful by reporting system latency and behavioral changes. It is certain and will be greatly affected. Overall, the predictions in this study show that Omicron can cause high levels of infections and hospitalizations, disrupting medical services.

*Important Notices

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