Having recently experienced another upswing in Covid cases during the summer period, it seems pertinent to examine the current state and probable future trajectory of the Coronavirus, which has been impacting the global health landscape for approximately four and a half years. Accordingly, let’s delve into the latest variants of the virus.
The Coronavirus has been evolving continuously since its emergence, something that was anticipated. We already witnessed the advent of potent strains such as Delta and the initial versions of Omicron in 2021. However, since Omicron’s introduction, various offshoots have risen to prominence and subsequently receded as new variants emerged. The JN1 variant made its first appearance in December 2023, and its subsequent lineages, F456L and R367, are the most commonly seen worldwide at present, as per data from the Health Protection Surveillance Centre (HPSC).
The term FLiRT has been formulated to encapsulate an assortment of variants, comprising KP.2, JN.1.7, and other types starting with KP or JN. These branches independently acquired the same set of mutations and are all fundamentally rooted in the JN.1 variant, prevalent in the current year. The specific mutations given the name FLiRTs denote precise positions in the spike protein.
Frequent mutation is a trait of viruses such as Sars-CoV-2. These mutations often help the virus to avoid detection by our immune system’s antibodies, albeit at the cost of reducing its ability to attach to the cells it aims to infect. Subsequent mutations often restore this capability. Despite continual mutational changes, the overall make-up of Covid has not shifted dramatically in the last two years.
A risk assessment from the World Health Organisation implies that JN1 has the potential to circumvent existing immunity, but it is unlikely to be linked with increased infection severity. This assertion is supported by the epidemiological figures from Ireland. Data from HPSC indicates that the country’s summer surge saw a peak of 1,000 cases between week 22 and week 25, before a slight decline. This increase was particularly evident in individuals over 65 years of age. Although hospitalisation rates rose in parallel with the surge, intensive care admissions and death rates remained stable, suggesting no associated increase in infection severity.
What is causing the spike in Covid cases during the summer?
It’s important to understand that this isn’t an exclusively summer phenomenon. Over the past five summers since the Covid-19 outbreak, there has been a noticeable increase in Covid infections to varying degrees. As outlined in a recent analysis by Stat magazine, several reasons could potentially explain this summer increase. Primary reasons being the mutation of the virus, especially with the emergence of the Omicron variant, has significantly enhanced its transmission capability and people’s vulnerability to reinfection in a relatively short time after their last infection or booster dose.
Two factors contribute to this pattern: the natural decrease in immunity to the Sars-CoV-2 virus over a span of three to four months, and the virus’s ongoing evolution to infect individuals who have multiple defence layers.
The pattern of summer surges and winter spikes has led to a hypothesis among some experts of the virus demonstrating a cyclical pattern, with potential waves of infection occurring approximately every six months. This pattern is likely due to the periodic reintroduction of susceptible individuals into the population.
Could the virus eventually conform to an annual winter infection cycle?
At present, there’s no substantial evidence to suggest that this shift to a winter cycle is likely. Indeed, most experts express scepticism about this seasonal pattern emerging. As one expert emphasises, the time delay between the emergence of new variants and the release of compatible vaccines continues to be a major obstacle to achieving this seasonal cycle.
Dr Aaron Glatt, a representative of the Infectious Diseases Society of America, stated “It’s crucial for people to comprehend that we’re likely going to continue battling Covid for many more years. Infection peaks and troughs will occur, irrespective of the season.”
The future trajectory of the virus remains uncertain, with many key aspects still needing exploration and understanding.