Fatality Rates After Infection With the Omicron Variant (B.1.1.529): How Deadly has it been? A Systematic Review and...

Area of Science:

• Epidemiology
• Infectious Diseases
• Public Health

Background:

• The SARS-CoV-2 pandemic, ongoing since late 2019, has been significantly impacted by the emergence of new variants.
• The Omicron variant, identified in November 2021, presented new challenges in understanding disease severity and transmission.
• Assessing the impact of variants and the efficacy of interventions like vaccination is crucial for public health strategies.

Purpose of the Study:

• To evaluate the severity of the Omicron variant of SARS-CoV-2.
• To quantify the effectiveness of vaccination in reducing mortality rates associated with the Omicron variant.
• To compare Omicron variant mortality with previous SARS-CoV-2 variants.

Main Methods:

• A systematic review and meta-analysis were conducted.
• Data from 270 articles published from November 2021 onwards were analyzed.
• The analysis included data from 3,214,869 patients infected with the Omicron variant.

Main Results:

• A total of 6,782 deaths were recorded among Omicron-infected patients, representing a mortality rate of 0.21%.
• The pooled mortality rate across analyzed articles was 0.003, with a pooled in-house mortality rate of 0.036.
• Vaccination was found to be effective in preventing death, with an odds ratio of 0.391 (p < 0.01).

Conclusions:

• Mortality rates associated with the Omicron variant are lower compared to the preceding Delta variant.
• mRNA vaccination provides robust and effective protection against severe illness and death caused by the Omicron variant.
• Vaccination remains a critical tool in mitigating the impact of SARS-CoV-2 variants.