KOBE -- The majority of patients who contracted the coronavirus in or after the spring of 2020 had antibodies effective against various mutant strains, including the Delta variant first found in India, according to results announced on July 13 by a team including Kobe University researchers.
Many of the COVID-19 patients are thought to have been infected either with the original coronavirus strain or the Alpha variant, which has origins in the United Kingdom.
Yasuko Mori, a clinical virology professor at Kobe University, commented, "There is a possibility that individuals who were infected have a low risk of getting infected again with another mutant strain, as well as developing severe symptoms."
The research team conducted analysis on 81 COVID-19 patients at the Hyogo Prefectural Kakogawa Medical Center, and examined the amounts of antibodies contained in the blood serum of individuals one month after they developed symptoms.
All research subjects possessed antibodies effective against the original coronavirus strain and the Alpha variant. The study also found that 78 people had antibodies effective against the Beta variant first found in South Africa, and all but one individual had antibodies effective against the Gamma variant which has spread in Brazil.
The levels of antibodies seen in the patients were around the same for the Alpha variant and the original strain. On the other hand, the values of antibodies that could counter the Beta and Gamma variants tended to be smaller.
As for the time of infections, 18 people were infected during the first coronavirus wave between March and June 2020, while 20 individuals contracted the virus during the second wave between July and October 2020, 23 people during the third wave from November 2020 to February 2021, and 20 during the fourth wave, which began in March 2021.
Three patients were selected from each coronavirus wave, and all 12 sampled individuals had antibodies effective against the Delta variant.
When breaking down patients by the scale of their symptoms, there were 37 people with "extremely severe symptoms" who required ventilators, 19 individuals with moderate or severe symptoms, and 25 individuals with mild or no symptoms. For all variant types, there was a tendency for antibody levels to be higher the more severe the patients' symptoms were.
In addition, the team researched the amounts of antibodies in 68 doctors working at Kobe University Hospital who have received two shots of the Pfizer vaccine, and found that they possessed antibodies effective against all mutant strains, including the Delta variant.
(Japanese original by Satoshi Kondo, Osaka Science & Environment News Department)