The ‘double-whammy’ of global warming and a wet March means there is an increased chance of high pollen levels this April. That means a potential surge in Covid cases and allergy sufferers should prepare for an early start to the hay fever season, warns a leading testing expert.
Dr Avinash Hari Narayanan (MBChB), Clinical Lead at London Medical Laboratory, says: ‘This spring could see higher pollen counts than normal, because of an unfortunate combination of weather conditions. Not only is this likely to lead to an early start to hay fever and other spring allergies, but there’s convincing evidence that it could create the perfect storm, resulting in increased Covid infections.
‘Global warming is leading to an earlier, longer, spring pollen season here in the UK. The Met Office has warned changes in temperature and rainfall may lengthen the UK pollen season and potentially make atmospheric pollen concentrations higher.
‘You might think that the drier the early spring the higher the pollen count but the opposite is true. A dry season reduces the amount of pollen production, whereas spring rainfall increases it. The early signs are ominous, with March having been so wet.
‘Low temperatures during the winter keep plants and trees dormant for longer into the new year. The lower the temperature, the less pollen is produced. However, December and January’s temperatures were close to the average this winter and February was notably warmer than normal. That means we’re on course for a high spring pollen count.
‘Not only does that mean increased cases of spring allergies such as hay fever, but it could also mean higher Covid levels. A 2021 paper by an international team of scientists, published in the “Proceedings of the National Academy of Sciences” (PNAS), found that higher airborne pollen concentrations correlated with increased Covid infection rates. The research spanned 31 countries and presents the most comprehensive dataset in this research area.
‘It has been recognised for some time that exposure to airborne pollen enhances susceptibility to viral respiratory infections. This research specifically examined the link between Covid infection rates and pollen concentrations. It revealed what the scientists termed a “robust and significant positive correlation between SARS-CoV-2 infection rates and airborne pollen concentrations”.
‘Whether this is a result of complex immune system interactions, or increased transmission due to hay fever symptoms compounded by diminishing face mask use, or both, remains to be determined, but its impact is palpable.
‘The team concluded that it was impossible to completely avoid exposure to pollen, recommending and encouraging particle filter mask use among high-risk individuals during high springtime pollen concentrations.
‘As well as potentially increasing the number of Covid cases, pollen is also responsible for many, sometimes severe, allergic reactions. Global warming is having an impact on the types of pollen and allergens we are facing in the UK.
‘New University of Michigan research reveals that, by the end of this century, global pollen emissions could begin up to 40 days earlier in the spring, compared to 1995. Allergy sufferers could see that season last an additional 19 days before high pollen counts subside, resulting in prolonged allergen exposure.
‘As the average UK temperature rises, new species of plants, grasses and trees are taking root here. These bring with them new pollens and a gradual shift in pollen seasonality and densities, potentially triggering allergies in people who have never suffered from problems such as hay fever.
‘While wearing a particle filter mask is an understandable precaution for at-risk individuals worried about the impact of Covid, most people will consider it an overreaction to the risk presented by spring allergies. That said, there is growing interest in understanding allergic risk, suggesting a gradual holistic shift from treatment to prevention. That’s why increasing numbers of people are testing for typical allergies before they ever suffer a reaction.
‘Allergy testing was once costly, difficult to access and yielded narrow testing windows, but the evolution of immunology and technology has vastly improved things. Today, allergy testing is a single finger-prick blood test that will identify a wide array of potential allergic triggers, including pollen, pet hair and both plant and animal-derived allergens. For example, London Medical Laboratory’s Allergy Complete is the UK’s most comprehensive allergy test, analysing 295 allergens.
‘Tree pollens will be the first to hit Brits this year. As new tree species arrive in the UK, they can trigger early spring allergic reactions in people who have never had them. That’s why LML’s test covers not just many typical British trees, but many non-native varieties. These include: Acacia, Alder, Arizona cypress, Ash, Beech pollen, Cottonwood, Cypress, Date Palm, Elm, Hazel, London plane tree, Mountain cedar, Mulberry tree, Olive, Paper mulberry, Silver birch, Sugi pollen, Tree of heaven, Walnut and Weeping fig.
‘The test includes grass, weed and flower pollens, as well as a wide variety of insect venoms, such as potentially fatal allergies to bee and wasp stings. Everything from dust mites and pet hair to fruit, eggs, nuts, fungi and moulds are also covered. It can be taken at home through the post, or at one of the many drop-in clinics that offer it across London and nationwide in over 95 selected pharmacies and health stores.
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