A research group at Kobe University has determined the amount of antibody against the new coronavirus contained in the serum of 2021 people who underwent a health examination at the Hyogo Prefectural Health Foundation (Hyogo Ward, Kobe City) from July 7 to August 19, 8. Analyzed.As a result, it was found that the percentage of people who are thought to have a history of infection with the new coronavirus has increased five-fold compared to a similar survey as of October 6.
According to reports, the prevalence of antibodies against the N protein obtained by infection with the virus (not obtained by vaccination) was 1,000% in 21 out of 2.1 people.This result means that the infection rate of the new coronavirus based on PCR at the time of analysis was 0.85% in Hyogo prefecture and 0.80% nationwide, but in fact 2.5 times that number was infected. do.In addition, the antibody prevalence rate for N protein was 2020% among 10 people who underwent a health diagnosis at the same Hyogo Prefectural Health Foundation in October 1,000, so this result is five times that.
On the other hand, the prevalence of antibodies against the S protein obtained by vaccination was 38.7%.The vaccination rate in Hyogo Prefecture as of August 2021, 8 was 6% for the first vaccination and 42.10% for the second vaccination, which is a result that largely reflects this figure.
In particular, the prevalence of antibodies to S protein was as high as 60% in the elderly aged 74.4 and over, and conversely, the prevalence of antibodies to N protein was low.It seems to reflect the results of priority vaccinations given to the elderly.
It is believed that more than 40% of people infected with the new coronavirus are asymptomatic (subclinical infections), and PCR and antigen testing alone may mislead the actual spread of the virus.The large-scale survey of antibody prevalence in serum by this study is more reliable and is considered to be valuable data showing the relationship between the spread of the new coronavirus and vaccination.
Paper information:[MedRxiv] Large-scale seroepidemiologic surveillance of COVID-19 – Cross-sectional study in Hyogo prefecture of Japan in August, 2021
