Covid cases are on the rise in the UK, but with winter quickly approaching, how might the virus evolve? We spoke to an expert to find out more about how vaccines, immunity and Covid variants might change during the colder months.
Martin Michaelis, professor of molecular medicine at the University of Kent, said “predicting what is going to happen with Covid-19 is like predicting the results of football matches - some outcomes are more likely than others”. Every time the coronavirus that causes Covid-19 replicates, it mutates, which means that “nature throws a dice with uncertain and unpredictable outcomes,” he added.
Although it’s not yet certain what will happen with the virus this winter, there is still a “general expectation” that respiratory illnesses like Covid “spread more effectively in the autumn and winter”, when the weather gets worse and people spend more time in poorly ventilated indoor spaces, Prof Michalis said.
However, he noted that Covid is “not yet following such a seasonal pattern” and we do not know whether it will in the future. But, after the Covid numbers had fallen for a while, they have now started to rise again, and, given that we are heading towards the colder months, it seems likely “that the Covid cases, hospitalisations, and deaths will further increase,” he added.
It currently remains unclear at which point the current Covid surge will level off and decline again, and, if this happens, whether it will be followed by another wave, he said. This will primarily be dependent on the properties of the Covid variants in circulation.
The last two Covid waves were caused by Omicron sub variants - the first one by BA.1 and BA.2, and the second one by BA.4 and BA.5. Data has suggested that the currently dominating Omicron subvariant BA.5 may be in the process of being replaced by other Omicron sub variants including BQ.X, BA.2.75.2, and BF.7.
Data has also shown that these three new Omicron sub variants appear to be spreading faster and are better at overcoming immune protection provided by vaccines and previous infections than BA.5, Prof Michaelis said. But it’s not yet known whether they may be more or less severe diseases compared with previous Omicron sub variants.
Although Prof Michaelis said it “seems unlikely” that they could be substantially worse than BA.1 and BA.5, we “cannot be sure yet”. If new Omicron sub variants do cause a high number of infections, they will still result in an increase of severe cases, hospitalisations, and deaths, “even if they are not more deadly than previous ones,” he added.
However, disruptions at the scale that we experienced at the beginning of the pandemic, prior to the introduction of Covid vaccines, “seem at this moment in time highly improbable”. But, as it is “always possible” that a new variant could emerge that is not on the radar and which behaves in a “very different way”, the chance of another wave that “causes major disruptions” can “never be excluded with certainty”, Prof Michaelis said.
Can a Covid wave be prevented?
The impact of Covid this winter will also “partially depend on our own conduct,” said Prof Michaelis. He said immune protection provided by vaccinations and previous infections wanes over time, which means we all become successively more vulnerable to Covid again.
“This is why everyone who is eligible should come forward and get their Covid booster,” he said.
Prof Michaelis explained that we can also all “consider adapting our behaviour” in order to reduce the spread of Covid and the likelihood of another massive surge. For example, wearing face masks in crowded, poorly ventilated spaces such as on public transport and in supermarkets, and washing our hands regularly.
Lower levels of Covid spread not only reduce the likelihood of disruptions, but they also protect vulnerable individuals with immune defects who are at a high risk from the virus and cannot “effectively protect themselves by vaccination,” he said.
These prevention measures will also help to keep other respiratory illnesses at bay that already put pressure on the NHS during the winter prior to Covid. Prof Michaelis noted that a “severe flu season may be on its way”, based on Australia recently experiencing this, which “usually forebodes what we should expect in the UK”, and recommends getting a flu jab too.