PNAS:  Pollen is likely to increase the risk of COVID-19 infection

PNAS:  Pollen is likely to increase the risk of COVID-19 infection.  Spring is here, and pollen comes with it. According to a report on the Medicalxpress website, the Journal of the American Medical Association (PNAS) recently issued a warning that this year’s pollen season needs to be extra vigilant, because pollen is likely to increase the risk of COVID-19 virus infection.

Researcher Athanasios Damialis of the Environmental Medicine Center of the Technical University of Munich introduced that the outbreak of the COVID-19 virus in 2020 coincides with the pollen season in the northern hemisphere, so the influence of pollen on infection deserves special attention. In this study, the researchers collected pollen data from a total of 130 sites in 31 countries, and compared the pollen concentration with the infection rate, weather conditions, population density, and lockdown measures to assess the risk.

It was found that pollen factors accounted for 44% of all pathogenic factors in different regions, and humidity and temperature also had a certain influence. In some areas where no lockdown measures have been taken, the infection rate will increase by an average of 4% for every additional 100 pollen per cubic meter of air. In some German cities, there are more than 500 pollen grains per cubic meter of air, and the infection rate in this city is also 20% higher than that in other regions. In contrast, in areas subject to lockdown measures, the impact of infection caused by changes in pollen concentration has been reduced to half.

Why does pollen weaken the immune response? Damialis analyzed that when the virus enters the body, the infected cells secrete interferon and send signals to the surrounding cells to warn them to strengthen their defense against the virus and resist invaders; the inflammatory response is activated, which also helps fight the virus. However, if there is a large amount of pollen in the air, after these pollen grains and virus particles are inhaled together, the amount of interferon produced by the cells will be reduced, and the inflammatory response will also be reduced.

Previously, a large cohort study in South Korea stated that the worsening of asthma in preschool children is closely related to seasonal environmental factors, including ozone and tree pollen. Another study claimed that some compounds in pollen can down-regulate the production of interferon lambda in the respiratory epithelium of humans and mice. This interferon has antiviral effects. Influenced by pollen, they can affect human rhinovirus and respiratory syncytial virus. decrease of resistance.

Therefore, on days with higher pollen concentrations, the incidence of respiratory diseases increases, as does the new coronavirus pneumonia. The author specifically pointed out that whether or not suffering from hay fever has little effect on the risk of infection, everyone may be infected.

Damialis said, it can be seen that when we conduct disease publicity, we should remind people, especially high-risk groups, that high pollen concentrations in the air can lead to a higher risk of respiratory infections. When studying changes in the transmission rate of the new coronavirus, environmental factors such as local pollen must also be taken into account to increase the population’s awareness of the prevention of new coronavirus pneumonia and alleviation of outbreaks.

For vulnerable groups, it is recommended to stay indoors as much as possible to reduce exposure outside. If you go out, you need to pay close attention to the pollen report of the local meteorological department. When the pollen concentration is high, you need to wear a mask when you go out. In fact, the pollen grains are relatively large. Any kind of anti-allergic mask can effectively prevent inhalation. Of course, once you often sneeze and cough under the influence of pollen, you still need to wear a special mask to prevent the COVID-19 virus to prevent risks to others.

(source:internet, reference only)

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