Cross-Neutralizing Activity Against SARS-CoV-2 Variants in COVID-19 Patients: Comparison of 4 Waves of the Pandemic in Japan

Abstract

Background In March 2021, Japan is facing a 4th wave of SARS-CoV-2 infection. To prevent further spread of infection, sera cross-neutralizing activity of patients previously infected with conventional SARS-CoV-2 against novel variants is important but is not firmly established. Methods We investigated the neutralizing potency of 81 COVID-19 patients' sera from the 1st–4th waves of pandemic against SARS-CoV-2 D614G, B.1.1.7, P.1, and B.1.351 variants using their authentic viruses. Results Most sera had neutralizing activity against all variants, showing similar activity against B.1.1.7 and D614G, but lower activity especially against B.1.351. In the 4th wave, sera-neutralizing activity against B.1.1.7 was significantly higher than that against any other variants, including D614G. The sera-neutralizing activity in less-severe patients was lower than that of more-severe patients for all variants. Conclusions The cross-neutralizing activity of convalescent sera was effective against all variants but was potentially weaker for B.1.351. The high neutralizing activity specific for B.1.1.7 in the 4th wave suggests that the mutations in the virus might cause conformational change of its spike protein, which affects immune recognition for D614G. Our results indicate that individuals who recover from COVID-19 could be protected from the severity caused by infection with newly emerging variants.

Assessing Government Policies’ Impact on the COVID-19 Pandemic and Elderly Deaths in East Asia

“…As of 31 March 2022, Hong Kong has experienced five waves (see the appendix in [ 11 ] for the first four waves), while South Korea has dealt with four waves (see [ 12 ] for the periods of the first three waves). Japan has encountered its sixth wave ([ 13 , 14 ] define the periods from the first wave to the fifth wave of the COVID-19 pandemic), while Taiwan has faced four waves based on the period of level 3.…”

Number of public health nurses and COVID-19 incidence rate by variant type: an ecological study of 47 prefectures in Japan

“…The time of spread of each COVID-19 variant was defined with reference to previous studies in Japan [ 9 , 20 , 23 , 24 ]. Of the five waves of the COVID-19 pandemic in Japan, the period from January 16, 2020 to the third wave is the wild type, the fourth wave is the alpha variant, and the fifth wave is the delta variant.…”

Cross-neutralizing activity against Omicron could be obtained in SARS-CoV-2 convalescent patients who received two doses of mRNA vaccination

“…A positive SARS-CoV-2 antigen test or positive polymerase chain reaction (PCR) detection of the SARS-CoV-2 genome in nasal, nasopharyngeal, oropharyngeal, or saliva samples were used to confirm the diagnosis of COVID-19. We used the same definitions of severities as in our previous reports [10,□11]; ‘Asymptomatic’ patients had neither clinical symptoms nor hypoxia. ‘Mild’ patients had symptoms without evidence of pneumonia or hypoxia.…”

“…The virus neutralization assay against the four SARS-CoV-2 variants D614G, Alpha, Delta, and Omicron was conducted using each authentic virus as described [10,□11] at Biosafety Level 3.…”