The Pfizer-BioNTech Covid-19 vaccine will be distributed in Montreal, Quebec on November 24, 2021.
The Greek letter omicron was assigned to a new variant of Covid in South Africa.
The strain was recognized by the U.N. health agency as a variant of concern.
Health experts are concerned about the transmissibility of the omicron variant because it has an unusual constellation of mutations and a profile that is different from other variant of concern.
The WHO's technical lead on Covid-19 said in a video that Omicron is a variant of concern because it has some concerning properties. The variant has a large number of mutations and some of them have worrying characteristics.
It is feared that a large increase of Covid cases in South Africa's Gauteng province could mean that it has greater potential to escape prior immunity than other variant. The number of omicron cases appears to be increasing in almost all of South Africa's provinces.
When Covid strains are more transmissible, more virulent or more resistant to public health measures, they are labeled as a variant of concern by the organization. The data presented at the South Africa Department of Health on Thursday indicates that some omicron's genes are connected with improved resistance to vaccines.
The presentation at the briefing said that certain mutations could make omicron more contagious, while others haven't been reported yet.
The WHO said in a statement that preliminary evidence suggests an increased risk of reinfection with this variant.
Global markets fell into a tailspin on Friday after the designation of a new variant of concern and mounting alarm from health officials. Travel and leisure stocks took a big hit on the news.
It will take weeks for WHO to understand how the variant may affect diagnostics, therapies and vaccines.
The omicron variant contains around 50 different changes, but more than 30 of them are in the spike protein, which interacts with human cells prior to cell entry, according to a South African scientist.
The delta Covid variant, which spread rapidly earlier this year to become the dominant strain worldwide, has only two mutations, but the part of the virus that first makes contact with our cells has 10.
The chance to genetically evolve is the result of this level of mutation, which most likely came from a single patient who couldn't clear the virus. The hypothesis was proposed for the alpha Covid variant.
There is a lot of work being done in South Africa and other countries to better understand the variant in terms of transmissibility, severity, and impact on our countermeasures. There is little information so far.
In South Africa, around 100 omicron variant genomes have been identified. The variant has been found in several countries.
Health officials say that many of the omicron variant's genes are linked to increased resistance to the vaccine and may affect how the virus behaves with regard to inoculation, treatments and transmissibility.
People wait at an airport.
Sharon Peacock, professor of public health and microbiology at the University of Cambridge, said that there are two ways to go about it.
It is better to go hard, go early and go fast, and apologize if you are wrong, than to take an academic view that we need to reach a tipping point in evidence before action is taken. The rapid spread in South Africa could be due to a variety of factors. Peacock said there are enough red flags to assume the worst and take a precautionary approach.
The European Union, the U.K., Israel and Singapore are some of the countries that have imposed travel restrictions on southern African nations.
The WHO has warned countries against imposing travel restrictions quickly.
The U.K.'s decision to take precautionary measures seems to have been rushed as even the WHO is yet to advise on the next steps, according to the South Africa's foreign ministry.
CNBC's Elliot Smith contributed to the report.
