The COVID-19 double threat: variants and winter

As the world grapples with the rapid spread of the Delta variant, flu season is also approaching in Europe and North America. Despite availability of vaccines in these regions, these dual threats could increase risks for insurers.

The fast-spreading Delta variant has increased the risk that insurers could face well into next year as COVID-19 shows no signs of fading. Life and Health insurers in particular should remain watchful as excess mortality could remain elevated in 2022. With global vaccination efforts continuing at uneven rates from country to country, governments are taking varying approaches to combating the coronavirus’s spread. While some have lifted the strictest measures, such as in Britain and some parts of the United States, other European countries are mandating health passes for dining and public transport. Meanwhile, New Zealand, Australia and some East Asian countries continue to pursue a "zero COVID" approach with strict border controls, quarantine and early lockdowns.

The effects of these approaches remain uncertain. But as the Northern Hemisphere heads into the colder months and the traditional flu season, governments may need to reinstate some restrictions and other social distancing measures to combat COVID-19's potential seasonal effect. While deaths currently remain lower even in unvaccinated people than during previous waves of the pandemic, in part because infections are hitting younger populations, variants that reduce vaccine protections have the potential to drive up hospitalisation rates and the death toll again across the globe.

Delta is challenging our assumptions

Since its emergence in India, the Delta variant is now driving infections in nearly every country. The World Health Organization (WHO) has called Delta the "fastest and the fittest" variant. As it spreads, Delta's behaviour has challenged our previous assumptions about COVID-19 and how to contain it. The Delta variant appears to evade vaccine protections from primary infection more effectively than previous variants, though protection against severe disease remains high. Its greater viral load helps make it the most-infectious variant of the SARS-CoV-2 virus yet detected, bringing on symptoms more rapidly than the original virus. Some researchers say symptoms differ from "traditional" COVID-19 symptoms observed earlier in the pandemic, mirroring a common cold or hay fever, so people may not realise that they are infected and pass COVID-19 on to others.

The steady stream of variants that has emerged as the virus persists has led to resurgences in infections, raising questions about vaccine efficacy and creating uncertainty about whether herd immunity will be reached. It is therefore becoming increasingly important to monitor for potential waning immunity in those who have been vaccinated or who have recovered from active infections, especially among the vulnerable, including healthcare workers and the elderly, many of whom received doses more than six months ago. Israel is already administering COVID-19 vaccine booster shots, Europe and the United States are planning to do so in coming months, in hopes that refreshed immunity will extend protection through the 2021-22 winter. The United States this week just fully approved the Pfizer vaccine, which is expected to increase vaccination levels.

Vaccine protection against variants

Even in clinical studies of COVID-19 vaccines, no vaccine protected everyone against infection. Current vaccines target the spike protein where mutations, as seen in the Alpha, Beta, Gamma and Delta variants, have been shown to increase the transmissibility of the virus. Variants that produce increased viral load and greater infectiousness are expected to reduce the effectiveness of vaccines, leading to more so-called “breakthrough infections”.

As Delta spreads, however, data from Canada and Britain indicates that COVID-19 vaccines continue to provide high levels of protection against symptomatic disease, with even greater protection against severe disease and death. But studies indicate that existing vaccines offer varying degrees of reduced efficacy against variants, including Delta, with protection diminishing over time. The full picture is still developing, as studies had important differences, such as the timing of doses, the age of those studied and what researchers sought to measure, including protection against asymptomatic or symptomatic infection, hospitalisation or death. More research is needed, also on the degree to which vaccinated people who become infected with the Delta variant are infectious to others. The broad expert consensus, however, remains that vaccines are the strongest protection currently available against severe illness and death.

While vaccination for adults remains recommended across the world, the guidelines for children vary. In the UK, vaccination for those over 16 is recommended, whereas in the US, everyone over the age of 12 is eligible for a vaccine. Across the European Union, Moderna and Pfizer are authorised for children as young as 12, with rollouts being determined on a country-specific basis.

Possible seasonal effect

Respiratory diseases like the flu have a clear pattern, with many countries seeing significant waves during winter months. As people spend more time indoors, colder temperatures preserve viruses, and mucous membranes may dry out, making them more susceptible to viral infection. This is particularly notable in countries where seasons vary widely, such as in Europe and North America. As the Northern Hemisphere now approaches the winter flu season, questions remain over whether there will be a spike in COVID-19. Some remaining social restrictions, whether enforced by governments or self-imposed, are likely to lessen the impact of COVID-19 this year, but the true extent is yet to be seen. It is also possible the flu season will be more severe this year than in 2020-21, given relaxed COVID-19 restrictions, though this could be offset should more people opt for flu shots.

Many studies have sought to understand seasonal patterns of COVID-19, but a clear limitation on them is the short timeframe, since COVID-19 has only been prevalent since early 2020. Some research has shown that the transmissibility of SARS-CoV-2 can be affected by meteorological factors, including temperature and humidity. An environmental epidemiology study shows a consistent seasonality pattern in European regions with winter peaks in November, December and January. The study also indicates some regions in North America, North Africa and Asia show a similar pattern. Elsewhere, winter peaks appear heterogeneous, with a gradual shift from Southern Asia to Oceania. Seasonal changes in rates of infection may also be impacted by public health interventions, potentially making conclusions about the true seasonality of COVID-19 premature, considering the limited data and difficulties in assessing the impacts of social distancing.



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