The spring equinox arrived in March and with it came longer days, warmer temperatures and, for about eight percent of the world’s population, seasonal allergies. Prior to the SARS-CoV-2 pandemic, allergies were more of a nuisance than a serious health concern for most people. But beyond emotional duress stemming from the fact that seasonal allergy symptoms can resemble COVID-19 symptoms, there is some evidence suggesting those with seasonal allergies are more susceptible to COVID-19 Infection.
COVID-19 vs. Allergies
Both seasonal allergies and COVID-19 can affect structures of the respiratory system, but they are more different than the same. Let’s take a look at the most common symptoms of each condition to understand what to look for:
Runny nose, sneezing and itchy, watery eyes — These are the hallmark symptoms for someone who suffers from allergies caused by plant pollen, but these symptoms are rare or not present at all in people with COVID-19 infections.
Fever, cough, body aches, shortness of breath, and loss of taste and smell — These are common symptoms of COVID-19, with fever and cough being the most common, but they are almost never experienced by allergy sufferers. Some of the less-common symptoms of COVID-19, such as digestive issues and diarrhea, are also rare among people with allergies.
Still, there are a few symptoms shared by both conditions. These include sore throat, fatigue and headaches. It’s these overlapping issues that cause some of the confusion, and for individuals with asthma, deciphering symptoms can be even more challenging. That’s because asthma, which can be triggered by seasonal allergies, can also lead to shortness of breath and rapid breathing.
What the Science Says
The good news is that a year living with a global pandemic has provided plenty of opportunities to learn more about the interplay between seasonal allergies and COVID-19. Here are a few things we have come to discover:
Pollen exposure may weaken our ability to fight respiratory viruses — This research, conducted by a team of European scientists, actually predates the pandemic, but it provides evidence that conditions leading to seasonal allergies could make individuals more susceptible to viruses like SARS-CoV-2. The researchers found that pollen significantly diminished the immune response of airway epithelial cells to rhinovirus, which is responsible for the common cold. They also found that mice infected with respiratory syncytial virus (RSV) and simultaneously exposed to high pollen levels had a weakened antiviral response and increased numbers of virus in their pulmonary system.
Higher airborne pollen concentrations are linked to SARS-CoV-2 infection rates — The findings from the previous study were corroborated recently by scientists who studied the effects of pollen exposure specifically on SARS-CoV-2 infections at 130 sites in 31 countries. Publishing in the Proceedings of National Academy of Sciences, they shared findings that airborne pollen could explain, on average, 44 percent of the infection rate variability. When pollen concentrations were high for four days in a row, infection rates increased. In non-lockdown situations, an increase in pollen concentration by 100 pollen particles per cubic meter resulted in a four percent average increase of infection rates. Lockdown halved infection rates under similar pollen concentrations.
There is inconclusive and controversial evidence of the association between allergic diseases and the risk of adverse clinical outcomes of COVID-19 — This literature review, appearing in the February 2021 issue of Current Allergy and Asthma Reports, found conflicting evidence about the link between allergic rhinitis (AR) and COVID-19. In a Korean cohort study, AR was associated with an increased likelihood of SARS-CoV-2 test positivity and increased risk for death, ICU admission and invasive ventilation. Other studies found exactly the opposite — that AR patients had lower risk of hospitalization. The authors acknowledged that additional studies are necessary, but they still concluded that patients with allergic diseases should minimize hospital visits and avoid crowds of people.
Wearing a mask reduces the transmission risk of the SARS-CoV-2 virus, but it also reduces allergic rhinitis symptoms — The widespread mask-wearing of the pandemic provided a unique opportunity to study the effects of masks on the severity of seasonal allergy symptoms. Publishing in The Journal of Allergy and Clinical Immunology, a team of Israeli researchers collected data to suggest that face mask usage may reduce the severity of AR symptoms by reducing allergic responses. They attributed this reduction to the physical filtration capabilities of face masks and to the warm, humid environment created between a mask and an individual’s mouth and nose. These conditions appear to inhibit the immune response of nasal cells to the allergens responsible for seasonal allergies.
Key Takeaways for People with Seasonal Allergies
Given this research, it’s clear that the pandemic brings a dose of good news and bad news to allergy sufferers. Exposure to pollen may increase susceptibility to COVID-19 infection, but wearing a mask, which has become part of our daily routine since March 2020, can block pollen particles. Masks also create warm, moist breathing environments that decrease the intensity of our immune response when pollen does get inhaled. And, with the world in lockdown, people have tended to spend less time outdoors and, as a result, have had less exposure to plant pollen.
People with seasonal allergies should still be cautious, adhere to CDC guidelines for social distancing and avoid high-risk environments. They should also get vaccinated, according to the CDC, unless they have a severe reaction to one of the vaccine components, even if they have had strong allergic reactions to food, pets, venom, or latex in the past.
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