Sheba Medical Center found a 65% decrease in the hospitalization of severe asthma patients and a 45% drop in the number of urgent visits to the hospital’s emergency room by asthma sufferers in 2020 versus 2019. Prof. Nancy Agmon-Levin, who conducted the study, told The Jerusalem Post that she believes “masks blocked infectious agents and definitely pollen.” Agmon-Levin is the head of Sheba’s Clinical Immunology, Angioedema and Allergy Unit. She said that she and her team were hearing comments from patients that they had a lot less allergies this year compared to previous years. “We thought this is probably because of wearing masks, but thought about how we could prove the idea,” she explained. “We checked the referrals to the emergency department due to asthma, of which 80% to 90% of all asthma patients are due to allergies.” While there were such large decreases in asthma referrals, there was only around a 10% decrease in overall emergency department referrals during the same period.