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What is a Variant of Concern (VOC)?

A variant refers to a virus that has undergone a change or a mutation. All viruses can mutate over time, which usually does not create concern or substantial impact. However, when variants do have significant clinical or public health effects, they are identified as a “variant of concern” (VOC). These variants can affect the spread, transmissibility, and severity of the disease associated with the virus.

Why are COVID-19 variants a concern?

Variants of the COVID-19 virus are a concern because they are spreading more easily and may potentially cause more severe illness than the original form of the virus. The current RAT and PCR tests continue to effectively detect COVID-19 infection with all VOCs.

The ways in which the COVID-19 virus spreads has not changed and therefore public health and workplace safety measures continue to be vital in preventing the spread of VOCs.


What are the Variants of Concern?

Omicron Variant (B.1.1.529)

Omicron is the newest variant of COVID-19; the first case in Windsor-Essex was confirmed on December 14, 2021. It is now the most common COVID-19 variant in Ontario. 

Omicron has shown to be more contagious than all previous variants, and has the ability to infect those who have received two doses of a COVID-19 vaccine and as a result, it poses a threat to health system capacity. Current evidence is showing that three doses of vaccine provides greater protection against severe outcomes from an infection with the Omicron variant. Get your third dose of the COVID-19 vaccine as soon as you are eligible to ensure you have the best protection possible.

The majority of evidence is demonstrating that Omicron causes less severe disease than Delta. However, due to increased transmission and cases, the number of severe cases continues to pose a threat to health system capacity. Worldwide, data is being reviewed to determine the risk of severe disease from infection with Omicron.

Delta Variant (B.1.617.2)

The Delta variant was first identified in India in October 2020. Previously, Delta was the most common strain of COVID-19 in Ontario and Windsor-Essex County. Delta was shown to be more contagious, and some data suggests it may cause more severe illness, than previous variants.

Other Variants

Throughout the pandemic, several other VOCs have been identified around the world and Windsor-Essex County, such as Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), and Kappa (B.1.617.1). However, the VOCs with the most impact in Ontario are Delta and Omicron. The Public Health Agency of Canada, along with other health authorities around the world, continue to monitor and research all COVID-19 variants to better understand their transmission, symptoms, and prevention.  

For more information and resources on VOCs, visit Public Health Ontario’s website. For local data on high-risk COVID-19 cases and vaccinations, visit our Local COVID-19 Data page.


How Can We Protect Ourselves?

Although the virus has mutated, COVID-19 continues to spread in the same way. Maintaining appropriate and effective public health measures, such as physical distancing and personal protective equipment (PPE), continue to be effective and important measures to protect ourselves. Emerging evidence indicates that medical masks provide better protection against rapidly spreading variants. N95 or KN95 respirators provide the best protection and should be worn in public settings, when possible. Vaccination remains a crucial, safe, and effective way to prevent serious illness and reduce transmission of COVID-19. In addition, staying home when sick, washing your hands, limiting close contacts, and wearing masks are all important measures to help reduce the spread of COVID-19.

We must all do our part to prevent the spread of COVID-19, including the VOCs. For more information on protecting yourself from COVID-19, visit our Frequently Asked Questions page.

Does the vaccine work against variants?

Current evidence suggests that COVID-19 vaccines in Canada are effective at providing protection against the known variants of concern. Individuals who are unvaccinated or partially vaccinated remain at the greatest risk of infection and transmission. Achieving the highest vaccination rates possible remains key to reducing the risk of COVID-19 transmission and significant surges in cases. Receiving three or four doses of a COVID-19 vaccine provides the greatest protection against severe illness from all known variants.

Visit our vaccines webpage to learn more about COVID-19 vaccination and book your appointment.

What additional measures have been put in place?

Beyond vaccination, Canada’s best defence against new variants is limiting the spread, through enhanced screening and testing measures. The Government of Canada and the Canada Border Services Agency continue to implement enhanced border measures and/or travel restrictions. Travellers are urged to be aware of latest travel restrictions prior to any departure and/or arrival.

Provincially, the Ontario COVID-19 Genomic Network continues to actively monitor for all potential variants, including Omicron. Individuals who have symptoms or have tested positive should isolate immediately to prevent further spread.

How are cases of variants of concern of COVID-19 managed in the community?

VOC cases will be handled in the same manner as any other COVID-19 case. Community members with a confirmed or suspected VOC case should isolate immediately and notify their close contacts. For further details, read the guidance on isolation and testing.

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Last modified: 
Wednesday, January 26, 2022 - 2:33pm