Progressive Increase in Virulence of Novel SARS-CoV-2 Variants in Ontario, Canada, February to June, 2021

@inproceedings{Fisman2021ProgressiveII,
  title={Progressive Increase in Virulence of Novel SARS-CoV-2 Variants in Ontario, Canada, February to June, 2021},
  author={David N. Fisman and Ashleigh R. Tuite},
  booktitle={medRxiv},
  year={2021}
}
The period from February to June 2021 was one during which initial wild-type SARS-CoV-2 strains were supplanted in Ontario, Canada, first by variants of concern (VOC) with the N501Y mutation (principally alpha, beta and gamma variants), and then by the delta variant. We demonstrate that these emerging VOCs were associated with an increase in virulence, as measured by risk of hospitalization, intensive care unit admission, and death. Compared to non-VOC SARS-CoV-2 strains, and adjusting for… 
Age-Specific Changes in Virulence Associated with SARS-CoV-2 Variants of Concern
TLDR
SARS-CoV-2 VOCs appear to be associated with increased relative virulence of infection in all age groups, though low absolute numbers of outcomes in younger individuals make estimates in these groups imprecise.
Age-Specific Changes in Virulence Associated With Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Variants of Concern
  • D. Fisman, A. Tuite
  • Medicine
    Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America
  • 2022
TLDR
SARS-CoV-2 VOCs appear to be associated with increased relative virulence of infection in all age groups, though low absolute numbers of outcomes in younger individuals make estimates in these groups imprecise.
The Global Epidemic of the SARS-CoV-2 Delta Variant, Key Spike Mutations and Immune Escape
TLDR
This review summarizes and analyses the biological characteristics of key amino acid mutations, the epidemic characteristics, and the immune escape of the Delta variant, and hopes to provide scientific reference for the monitoring and prevention measures of the SARS-CoV-2 Delta variant and the development strategy of a second-generation vaccine.
Delta Variant: The New Challenge of COVID-19 Pandemic, an Overview of Epidemiological, Clinical, and Immune Characteristics
TLDR
Although reduced efficiency of vaccines on this variant and its higher pre-symptomatic transmissibility have made it complicated to control the disease, higher vaccination coverage and following sanitation rules can help control the outbreaks.
Epidemiology and Vaccine Efficacy of Delta Variant
TLDR
With the emergence of new variants of SARS-CoV-2 due to continuous mutations, it is suggested that vaccination plays a significant role in preventing the transmission of disease and disease severity.
Is the Infection of the SARS-CoV-2 Delta Variant Associated With the Outcomes of COVID-19 Patients?
TLDR
It is confirmed that older age and comorbidity increase the mortality rate of patients with COVID-19, and the patients infected by the SARS-CoV-2 Delta variant have a lower Ct value, implying that the Delta variant has a higher viral load, which might cause a more transmissible virus among humans.
Is the infection of the SARS-CoV-2 Delta variant associated with the outcomes of COVID-19 patients?
TLDR
It is shown that the patients infected by the SARS-CoV-2 Delta variant have a lower Ct value than the patientsinfected by the non-Delta variant, implying that the Delta variant has a higher viral load, which might cause a more transmissible virus among humans.
Associations between SARS-CoV-2 variants and risk of COVID-19 hospitalization among confirmed cases in Washington State: a retrospective cohort study
TLDR
Infection with a VOC results in a higher hospitalization risk, with an active vaccination attenuating that risk, and the findings support promoting hospital preparedness, vaccination, and robust genomic surveillance.
Temporal Analysis of SARS-CoV-2 Variants during the COVID-19 Pandemic in Nepal
TLDR
A need to structure public policy of Nepal to target the delta variant since it has become the predominant variant in Nepal, and to appropriately sample and sequence genomes of SARS-CoV-2 at regular intervals to understand the dynamics of variants in the population is highlighted.
Association of the Delta (B.1.617.2) Variant of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) With Pregnancy Outcomes.
TLDR
The objective of this analysis was to evaluate disease severity and maternal and neonatal outcomes during the fourth wave, largely representing the Delta variant of SARS-CoV-2, and to compare this cohort with a 2020 cohort of patients with COVID-19.
...
1
2
3
4
5
...

References

SHOWING 1-10 OF 38 REFERENCES
Estimated transmissibility and impact of SARS-CoV-2 lineage B.1.1.7 in England
TLDR
The rapid spread of VOC 202012/01 suggests that it transmits more efficiently from person to person than preexisting variants of SARS-CoV-2, which could lead to global surges in COVID-19 hospitalizations and deaths, so there is an urgent need to estimate how much more quickly this variant spreads.
Rapid Rise of S-Gene Target Failure and the UK variant B.1.1.7 among COVID-19 isolates in the Greater Toronto Area, Canada
TLDR
In order to pre-emptively plan and implement public health measures to control COVID-19 now and through the spring, accurate and up-to-date early warning systems for new variants, including B.1.1-CoV-2, are essential across North America and the globe.
Inflection in prevalence of SARS-CoV-2 infections missing the N501Y mutation as a marker of rapid Delta (B.1.617.2) lineage expansion in Ontario, Canada
TLDR
Delta is rapidly overtaking other SARS-CoV-2 variants in Ontario, and has a substantial transmission advantage, and an inflection in the proportion of cases missing the N501Y mutation from rapidly decreasing to rapidly increasing, may be an early warning signal for Delta lineage expansion.
Effectiveness of COVID-19 vaccines against variants of concern, Canada
TLDR
The findings suggest that even a single dose of these 3 vaccine products provide good to excellent protection against symptomatic infection and severe outcomes caused by the 4 currently circulating variants of concern, and that 2 doses are likely to provide even higher protection.
COVID-19 Hospitalizations, ICU Admissions and Deaths Associated with the New Variants of Concern
TLDR
Because the increased risk of COVID-19 hospitalization, ICU admission and death with VOCs is most pronounced 14 to 28 days after diagnosis, there will be significant delays until the full burden to the health care system becomes apparent.
Risk of hospital admission for patients with SARS-CoV-2 variant B.1.1.7: cohort analysis
TLDR
The results suggest that the risk of hospital admission is higher for people infected with the B.1.1-1.7 variant compared with wild-type SARS-CoV-2, likely reflecting a more severe disease.
Risk of hospitalisation associated with infection with SARS-CoV-2 lineage B.1.1.7 in Denmark: an observational cohort study
COVID-19 Case-Age Distribution: Correction for Differential Testing by Age
TLDR
Observed disease incidence and testing rates were highest in oldest individuals and markedly lower in those aged < 20, but standardizing morbidity and testing ratios eliminated temporal trends, providing a markedly different picture of the epidemic than seen with crude SMR or case-based incidence.
Risk Factors Associated With Mortality Among Residents With Coronavirus Disease 2019 (COVID-19) in Long-term Care Facilities in Ontario, Canada
TLDR
The risk of COVID-19–related death was elevated among LTC residents, highlighting the need for improved infection control, widespread testing, access to personal protective equipment, and other supports to protect this vulnerable population.
...
1
2
3
4
...