Research press release


Nature Medicine

Virology: Protective immunity to seasonal coronaviruses may be short-lasting

SARS-CoV-2に対する防御免疫が長くは持続しない可能性が、SARS-CoV-2に似た4種類のコロナウイルスに対する免疫について調べた研究で示唆された。今回、10人の健康な被験者を35年以上にわたって観察した症例研究の血清検体を使用して、同一の季節性コロナウイルスへの再感染が、最初の感染からほぼ1年後に頻繁に起こっていることを明らかにした研究がNature Medicine に掲載された。この結果からすると、ワクチン接種や自然感染による集団免疫の獲得を待つといった、長期間持続する免疫を必要とする対策を取る場合には、注意が必要となりそうだ。


L van der Hoekたちはまず、気道感染を引き起こす4種類のヒト季節性コロナウイルス(HCoV-NL63、HCoV-229E、HCoV-OC43、HCoV-HKU1)について調べ、これらのコロナウイルスに共通する性質は、SARS-CoV-2を含めたヒトコロナウイルス全てで見られると想定した。




The duration of protective immunity against SARS-CoV-2 may be short-lived, suggests a study investigating immunity to four other, similar coronaviruses. The findings from a case study of ten healthy subjects monitored over 35 years are published in Nature Medicine. Reinfection with the same seasonal coronavirus occurred frequently around one year after the initial infection, which suggests that caution may be needed when relying on policies that require long-term immunity, such as vaccination or natural infection to reach herd immunity.

Although there is limited evidence of reinfection after exposure to SARS-CoV-2, it is generally assumed that reinfection by coronaviruses does occur. To prepare for future waves of SARS-CoV-2 infection, it is essential to understand the length of immunity to reinfection.

Lia van der Hoek and colleagues examined four strains of human seasonal coronavirus — HCoV-NL63, HCoV-229E, HCoV-OC43 and HCoV-HKU1 — that cause respiratory tract infections. The authors hypothesized that the characteristics shared by these coronaviruses might be representative of all human coronaviruses, including SARS-CoV-2.

To find out how often seasonal coronavirus infections occur, the authors examined a total of 513 serum samples collected at regular intervals since the 1980s from ten healthy adult males in Amsterdam. The authors measured increases in antibodies to the nucleocapsid protein — an abundant coronavirus protein — for each seasonal coronavirus. An increase in antibodies was considered a new infection. They observed 3 to 17 coronavirus infections per patient, with reinfection times between 6 and 105 months. Reinfections were frequently observed at 12 months after the initial infection.

The authors also found that blood samples collected in the Netherlands during June, July, August and September had the lowest rate of infections for all four seasonal coronaviruses, which indicates a higher frequency of infections in winter in temperate countries. The authors suggest that SARS-CoV-2 may share the same pattern after the pandemic.

Although further research with larger cohorts is needed, the authors conclude that reinfections occur frequently for all four seasonal coronaviruses, which suggests that it may be a common feature for all human coronaviruses, including SARS-CoV-2.

doi: 10.1038/s41591-020-1083-1


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