Dr Richard Pebody, who leads the High-threat Pathogen team at WHO/Europe, answers questions to unpack more about why the COVID-19 virus changes, what implications this has for public health, and what you as an individual can do to help and to stay safe.
Why do viruses change?
“First of all, I’d like to say that all viruses, including the COVID-19 virus, change over time as a natural phenomenon. Having said that, new variants of concern continue to challenge our pandemic response.
“When a virus replicates or makes copies of itself as it spreads, the virus genome (the set of genetic instructions for the organism) often changes a little bit. These changes are called mutations, and are usually not significant. A virus with one or several new mutations is referred to as a variant of the original virus.
“The more viruses circulate, the more they may change. These changes can occasionally result in a virus variant that is better suited to its environment than the original virus. This process of changing and selection of successful variants is called virus evolution.”
Why are some variants of COVID-19 causing more concern than others?
“WHO and its partners have been closely following the changes in SARS-CoV-2 (the COVID-19 virus) since January 2020. Most changes have had little to no impact on the virus’s properties; however, some are now known to affect, for instance, transmission (for example, the virus may spread more easily) or severity (for example, it may cause more severe disease).
“Systems have been set up to detect the various signals of potential variants of concern and to assess these based on the risks they pose to global public health. WHO is tracking these variants across the world.”
What are the main variants of concern at the moment and where are they spreading?
“There are currently 4 main variants of concern that continue to be detected and monitored in an increasing number of countries and territories around the world.
“The most prevalent variant currently circulating in the WHO European Region is SARS-CoV-2 B.1.1.7. This variant was first detected in the United Kingdom and has now spread widely to many countries in the Region and elsewhere. Two other variants of concern have also been found in South Africa and Brazil.
“On 11 May 2021, the B.1.617 (the variant originally identified in India) lineage of viruses was also added to the list of WHO- classified global variants of concern. Since their first detection in October 2020, there have been reports of these variants in countries throughout the world, with the largest number of cases detected in India, followed by the United Kingdom (where the sub-lineage B.1.617.2 has been designated a national variant of concern).”
Are we likely to see many more variants? Is this concerning?
“As COVID-19 continues to spread, we will see more variants emerge. Most of these will be inconsequential; however, it is possible that we will see further variants that are more transmissible or cause more severe illness.
“WHO and its partners have sophisticated surveillance systems in place to identify new variants, track their spread and assess their severity.”
How exactly are new variants identified and tracked?
“Since the start of the outbreak, WHO has been working with a worldwide network of expert laboratories to support testing and gain a better understanding of the COVID-19 virus.
“Research groups have sequenced the virus variants – meaning that they have ‘read’ the genetic code that makes up the genome – and shared these on public databases, including the GISAID Initiative. This global collaboration allows scientists to access global data to better track the virus and how it is changing.
“WHO’s global SARS-CoV-2 laboratory network includes a dedicated Virus Evolution Working Group, which aims to detect new mutations quickly and assess their possible public health impact.
“Many countries are also doing their own sequencing of COVID-19 variants and sharing this data internationally to help with global monitoring and responses.”
Do virus changes affect the effectiveness of vaccines?
“The COVID-19 vaccines that are currently being rolled out through vaccination programmes are expected to provide at least some protection against new virus variants because they all lead to a broad immune response.
“If any of these vaccines prove to be less effective against one or more variants, it will be possible to change the composition of the vaccine to protect against those variants.
“WHO continues to work with researchers, health officials and scientists to understand how these variants affect the virus’s behaviour, including their impact on the effectiveness of vaccines.”
Will the spread of new variants affect the easing of lockdowns and reopening of societies?
“Variants are a common phenomenon and are not in themselves dangerous, but they can be if they change the behaviour of the virus.
Therefore, we need to monitor these developments closely, keeping track of the progress of variants among populations and taking the most appropriate steps to contain and control them. This is key to preventing them from getting out of control.
“This does not necessarily mean further lockdowns, but these can’t be ruled out as one of the tools in the toolbox for dealing with community virus spread, particularly if a specific variant of concern is associated with higher transmissibility.”
Should people travel abroad while there are variants circulating?
“We are still in the midst of the pandemic, with high numbers of COVID-19 cases, a number of variants of concern in circulation and a large proportion of Europe’s population still unvaccinated. WHO still recommends that travel only be undertaken in essential circumstances: for emergencies, humanitarian actions, movement of essential personnel and by those in certain transport sectors.
“Those with illnesses and people at risk, including older travellers and people with serious chronic diseases or underlying health conditions, should postpone international travel to and from areas with known community transmission.”
What should people do to protect themselves from being infected by a COVID-19 variant?
“Vaccination will not bring an end to this pandemic until it is distributed to everyone around the world. While this progresses, we need to keep reducing the chance of the virus spreading, reducing our risk of being exposed and reducing the risk of exposing others to the virus.
“Our message is clear: people should continue to follow the recommended measures – what we refer to as public health and social measures – to reduce virus transmission. This includes washing hands frequently, wearing a mask, keeping at least 1 metre of physical distance, ensuring good ventilation, and avoiding crowded places or closed settings. These measures work against all variants by reducing the amount of viral transmission and decreasing the chances of the virus being able to further mutate.
“In addition, it is important that people take up their offer of a vaccine when their turn comes. As more people get vaccinated, we expect virus circulation to decrease, which will also lead to fewer mutations.”
What are WHO’s recommendations to countries regarding virus changes?
“Countries need to increase the sequencing of SARS-CoV-2 variants and report the results so that we can continue to increase our understanding of them and to develop effective responses.
“WHO urges the continuing and redoubling of all basic public health and social measures that are known to work. For countries, these also include testing, isolating and treating cases, contact tracing, and quarantine for contacts of cases.
“Although rates of transmission are still currently high, overall we are seeing the number of COVID-19 cases decreasing across the European Region.
“But we’ve been here before: when the curve flattens, it is not the time to drop our guard but to raise it higher so we do not have to return to a lockdown situation. Complacency is not our friend.”
