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Linked Clusters of SARS-CoV-2 Variant B.1.351 - Maryland, January-February 2021
MMWR. Morbidity and Mortality Weekly Report
|April 29, 2021
Summary
The first U.S. clusters of the SARS-CoV-2 B.1.351 variant were found without international travel links. This highlights the need for enhanced genetic surveillance and public health measures to control concerning variants.
Area of Science:
- Virology
- Epidemiology
- Public Health
Background:
- The SARS-CoV-2 B.1.351 variant, first identified in South Africa, may evade immune responses from prior infection or vaccination.
- This variant of concern (VOC) poses a potential threat due to reduced neutralization by antibodies.
- Early detection and containment are crucial for managing novel SARS-CoV-2 lineages.
Purpose of the Study:
- To investigate the initial linked clusters of the SARS-CoV-2 B.1.351 variant in Maryland.
- To understand the transmission dynamics and characteristics of these early U.S. B.1.351 cases.
- To assess the need for enhanced surveillance and control strategies for SARS-CoV-2 variants.
Main Methods:
- Public health authorities utilized contact tracing to identify individuals exposed to an index patient with the B.1.351 variant.
- Genetic sequencing was performed on additional specimens from identified clusters to confirm the presence and relatedness of the B.1.351 variant.
- Case investigations included inquiries into recent travel history, vaccination status, and prior infection history.
Main Results:
- Two linked clusters involving 17 patients with the SARS-CoV-2 B.1.351 variant were identified in Maryland.
- Sequencing confirmed the B.1.351 variant in three additional linked cases, closely related to the index patient.
- None of the 17 patients reported recent international travel, suggesting community transmission.
- Two patients had received their first COVID-19 vaccine dose within two weeks of exposure; one had a prior infection.
Conclusions:
- These findings represent the first identified linked clusters of the B.1.351 variant in the U.S. with no clear link to international travel.
- The study underscores the critical need to expand genetic surveillance for SARS-CoV-2 variants.
- Comprehensive contact investigations and universal prevention strategies (vaccination, masking, distancing) are essential for controlling the spread of VOCs.
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