Articles / Coronavirus
When will coronavirus end?
Vaccine effectiveness, herd immunity and variants are all deciding factors when it comes to ending the COVID-19 pandemic.
What is herd immunity?
Herd immunity is when a large enough proportion of a population is protected from infection, either through vaccination or immunity developed after a previous infection, to prevent transmission. When a large enough percentage of the population is protected, the virus cannot spread from person to person, as there are not enough people who are susceptible to infection for the disease to spread.
The World Health Organization has stated that the best way to achieve herd immunity from coronavirus is through vaccination, as to do so through infection of the entire population “would result in unnecessary cases and deaths”.
How many people need to be vaccinated for the UK to reach herd immunity?
The percentage of the population that needs to be vaccinated in order to achieve herd immunity from a disease varies, based on its level of infectiousness and transmission patterns. For measles, for example, this figure is 95%. It is difficult to know how many people will need to be vaccinated against COVID-19 in order for herd immunity to be achieved.
Scientists have suggested that the threshold for herd immunity for coronavirus is between 60 - 80%.
However, some experts are now also suggesting that herd immunity might be out of reach, due to vaccine hesitancy, no vaccinations for children, and the rise of new variants. This does not necessarily mean that there will be no return to normality, but that it will be difficult to achieve this through herd immunity.
What are coronavirus variants?
All viruses naturally mutate over time, which creates new random variations of the original virus. Since the outbreak of COVID-19, there have been many such small mutations in its genetic code, which in most cases has not made any significant difference to the way the virus infects people.
In some cases though, mutations have resulted in new virus variants with features that are more beneficial to the virus, making it more infectious, less treatable, or less detectable. These variants are considered to be a “variant of concern” by the UK government and are closely monitored.
The so-called “Kent variant”, which was first discovered in the UK in September 2020, is associated with higher infection rates in the areas where it is prevalent. This is because this variant has mutations that make it easier for the virus to infect people.
Variants of coronavirus discovered in South Africa and Brazil are also thought to be more infectious. There is also a possibility that this is because these variants can escape antibodies (proteins that defend your body from infection) to coronavirus which are present in the blood.
Are the new variants more deadly?
It is difficult to tell whether the new variants are more deadly, however, preliminary evidence collected by the government has suggested that the Kent variant is 30% more deadly.
Vaccine immunity and variants
It is important for scientists to understand how coronavirus mutates, and what those mutations mean for immunity to the virus. Three highly effective vaccines have been approved for use in the UK, which are an important tool in the fight against coronavirus. According to Jonas Nilsen, MD and co-founder of Practio, “while the development of coronavirus vaccines is an important step towards the end of the pandemic, studies on new variants suggest that new mutations could allow the virus to escape the coronavirus antibodies that develop after infection.”
“It is possible that current vaccines will be less effective on emerging variants of coronavirus, and that might make it more difficult to reach herd immunity. New variants could hamper the efforts to build a high enough level of immunity within populations, and in the world as a whole.”
“Even though it could be difficult to eradicate coronavirus altogether, it does not mean that we cannot return to a more “normal” way of living. Vaccines will probably have to be updated each year in response to new variants, much like the flu vaccine is now. The most likely scenario for the future of coronavirus is that it will become less dangerous each year, eventually becoming something similar to the common cold.”
Will the vaccines work against the new variants?
The vaccines that have been approved for use in the UK already have been shown to be effective against the new variants identified so far.
A study on the effectiveness of the Oxford/AstraZeneca vaccine against variants suggests that it has a similar level of effectiveness on the Kent variant.
The effectiveness of the other vaccines against new variants is still being investigated, but early data suggests that they will still offer some protection against infection.