All viruses, including the Coronavirus, change over time resulting in the emergence of new variants, most without a direct benefit to the virus or other public health impacts. Since the pandemic began, many countries have reported the transmission of variants, most notably, Denmark, the UK, Northern Ireland, the USA, South Africa, Brazil and Japan. These reports have raised interest and concern around changes to transmissibility and severity of the virus as well as the impact of these variants on existing diagnostics, vaccines and therapeutics. The emergence of these variants has also reemphasised the urgency to suppress the transmission of the virus everywhere, globally, as the longer it has the opportunity to circulate, the more opportunity it has to change in ways that could make countermeasures less effective or make the virus more deadly.
Since COVID-19 was discovered, the WHO has setup a robust system globally in order to monitor and track changes in the virus. This system leverages the existing systems setup to monitor other infectious diseases such as influenza, HIV, tuberculosis, Ebola and polio. This consists of a network of labs with genomic sequencing capacities in 150 countries which are capable of detecting and quantifying detailed changes in the virus. The WHO’s activity also consists of epidemiological surveillance which is proactively searching for unusual changes.
The WHO is currently characterising variants as a ‘variant of interest (VOIs)’ or ‘variant of concern (VOCs)’ in order to help prioritize the global public health response. The threshold for the determination of a VO is relatively low in order to maintain sensitive surveillance for potentially important variants. In contrast, the threshold for the determination of a VOC is high in order to focus attention and resources on the variants with the highest public health implications, while reducing noise and unwarranted diversion of limited resources. There are currently three VOCs to be aware of, as per the table below.
|Name:||SARS-CoV-2 VOC 202012/01 or B.1.1.7||501Y.V2 or B.1.351||P.1|
|First detected:||United Kingdom||South Africa||Brazil / Japan|
|Earliest detection:||September 2020||August 2020||December 2020|
|Countries reporting cases (new in the past 7-days)||118 (7)||64 (6)||38 (6)|
Early data and studies indicate that all of the VOCs exhibit increased transmissibility although the severity of the virus appears to be unchanged. In addition, observations have been made which appear to show that some of the existing vaccines have a lower efficacy against the variant B.1.351. This has triggered scientists and companies to already start thinking about a 2nd generation of vaccines. That being said, these are early studies and observations which can often change once more robust data is available.
On the 15th March, Dr Kate O’Brien, WHO Director for Immunisation, Vaccines and Biologicals commented:
“As we get more information the very first observations are often adjusted for new information. I want to emphasise how early the information is and I’ll give you an example. The Novovax vaccine was tested in South Africa at a time when the variant (B.1.351) was initially found to be circulating. There was some information from an early study that being infected previously with COVID did not confer protection against being infected with the variant. With more data coming in, in fact that initial observation doesn’t seem to be holding up; it looks as if, if you were previously infected you do have protection to some large degree against the variant. Whether or not we need boosters, whether the vaccines need to be adjusted, whether we’ll go to multi-strain vaccines, these are all decisions that will have to be grounded on more information as it comes in. The second thing I just wanted to say is that we don’t have any evidence to say that for any variant or any vaccine combined with the variant the vaccines do not work. It’s really a question of at what magnitude they’re working. There’s really no product right now where we would say, this simply does not work at all against a variant. It’s not the way the immune system works, it’s not an all-or-none phenomenon and it’s really much more about the magnitude of the effectiveness of these products and that does vary according to age and other factors. The most important thing here is that as these vaccines are rolling out this is the time when transmission really needs to be driven down; the lower the transmission is the less likely it is that there will be emergence of variants.”
In addition, Dr Maria Van Kerkhove, WHO Technical Lead on COVID-19 commented:
“It’s really important that everyone out there understands that there is a very robust system globally that is tracking this virus, that is looking to not only find where there are cases, so that we can take appropriate public action so that we prevent the spread of the virus. But we’re also looking at any detailed changes in the sequence of the virus itself and this is done through genetic sequencing, epidemiologic surveillance in countries to look at trends in incidence going up, going down, if there’s anything unusual happening. Any of these changes need to be evaluated in a transparent, comprehensive and robust manner and what we are looking at now are variants of interest as well as variants of concern. There are a number of studies that are underway to look at transmissibility, to look at severity and we don’t yet know if some of those variants of interest will become variants of concern. As Kate has said, the vaccines still work against these virus variants. Public health and social measures also work against reducing transmission. So, it’s important that we take this do-it-all approach including vaccination. I do want to say that in the last week we have had an 11% increase in transmission across the world. Five of six WHO regions have seen an increase in transmission. It is not the time to let up. We have to continue to do everything that we can including all of the individual-level measures, the community-level measures, everything that we can to drive transmission down. If we allow this virus to spread, if we give it an opportunity it will. Adding vaccines and vaccinations where they can be used is an important tool in addition to the public health and social measures so please continue to follow the local recommendations, please make sure you keep your distance, you wear your mask, you wash your hands, you practise respiratory etiquette, you work from home if you can. Do everything that you can to limit your exposure to this virus and if you get infected the virus stops with you.”
Countries and territories reporting SARS-CoV-2 VOC 202012/01 as of 16 March 2021:
Countries and territories reporting SARS-CoV-2 variant 501Y.V2 as of 16 March 2021:
Countries and territories reporting SARS-CoV-2 variant P.1 as of 16 March 2021: