Prevalence of SARS-CoV-2–Specific Antibodies, Japan, June 2020

Yoshiyama, Takashi; Saito, Yasuki; Masuda, Kunitsugu; Nakanishi, Yoshiko; Kido, Yasutoshi; Uchimura, Kazuhiro; Mitarai, Satoshi; Suzuki, Tadaki; Nakagama, Yu; Kubota, Hiroshi; Satomi, Maki; Uchikoba, Sana; Ohnishi, Makoto; Wakita, Takaji; Kato, Seiya; Kato, Katsunobu

doi:10.3201/eid2702.204088

Cited by 30 publications

(39 citation statements)

References 8 publications

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“…NAT-based case detection in Japan had been counted on as a promising strategy, capable of thoroughly tracking SARS-CoV-2 transmissions, and identifying and sizing cluster infections (1). It was not until June 2020, when the first national seroprevalence survey was performed, that the Japanese realized their 3-8 fold underestimation of the actual spread of the disease within the society (3). With the aim of enhancing case detection for effective quarantine, especially among the pre-symptomatic or asymptomatic affected individuals, testing recommendations since then have shifted from a symptom-driven approach towards a rather universal approach.…”

Section: Discussionmentioning

confidence: 99%

“…A signal equal to or above a cutoff of 1.4 Index (S/C) and 50 AU/mL, respectively, was considered serologically positive. An orthogonal testing algorithm was adopted in order to idealize positive-predictivity and determine, with high specificity, the individuals who were truly sero-positive of SARS-CoV-2 specific antibodies (3). In this algorithm the individuals who initially tested positive for anti-nucleocapsid antibodies were tested with a second test targeting the SARS-CoV-2 spike antigen.…”

Section: Serological Testingmentioning

confidence: 99%

“…In support of the hypothesis, reports from later active screening studies have revealed a significant majority of SARS-CoV-2 infections to manifest atypical nonrespiratory presentations, or even at times remain asymptomatic (3). Such minimally symptomatic individuals, never to be suspected of COVID-19, lack the opportunity to undergo SARS-CoV-2 nucleic acid amplification testing (NAT), and together with those All rights reserved.…”

Section: Text-word Count Introductionmentioning

confidence: 99%

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Serological testing reveals the hidden COVID-19 burden among healthcare workers experiencing a SARS-CoV-2 nosocomial outbreak

Nakagama

Komase

Candray

et al. 2021

Preprint

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We describe the results of testing healthcare workers from a tertiary care hospital in Japan, which had experienced a COVID-19 outbreak during the first peak of the pandemic, for SARS-CoV-2 specific antibody seroconversion. Using two chemiluminescent immunoassays and a confirmatory surrogate virus neutralization test, serological testing unveiled that a surprising 42.2% (27/64) of overlooked COVID-19 diagnoses had occurred when case detection had relied solely on SARS-CoV-2 nucleic acid amplification testing. This undetected portion of the COVID-19 iceberg beneath the surface may potentially have led to silent transmissions and triggered the spread. A questionnaire-based risk assessment was further indicative of exposures to specific aerosol-generating procedures, i.e. non-invasive ventilation, having had conveyed the highest transmission risks and served as the origin of outbreak. Our observations are supportive of a multi-tiered testing approach, including the use of serological diagnostics, in order to accomplish exhaustive case detection along the whole COVID-19 spectrum.

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Section: Discussionmentioning

confidence: 99%

Section: Serological Testingmentioning

confidence: 99%

Section: Text-word Count Introductionmentioning

confidence: 99%

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Serological testing reveals the hidden COVID-19 burden among healthcare workers experiencing a SARS-CoV-2 nosocomial outbreak

Nakagama

Komase

Candray

et al. 2021

Preprint

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“…The seropositivity for both assays was determined as per the cutoff values provided by the manufacturers. The positive cutoff antibody titer was defined as >0.10 AU/mL for IgG and 0.20 AU/mL for IgM [ 9 ].…”

Section: Methodsmentioning

confidence: 99%

Side effects and antibody titer transition of the BNT162b2 messenger ribonucleic acid coronavirus disease 2019 vaccine in Japan

Izumo

Kuse

Awano

et al. 2021

Respiratory Investigation

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Background The coronavirus disease (COVID-19) has afflicted large populations worldwide. Although vaccines aroused great expectations, their side effects on Japanese people and the antibody titer transition after vaccination are unclear. Methods The side effects of the BNT162b2 mRNA COVID-19 vaccine in participants who received vaccination at our center were investigated. Some participants were also surveyed for the antibody titer transition. Results In this study, 983 and 798 Japanese participants responded to the first and second doses, respectively. Side effects occurred in 757 (77.0%) and 715 participants (90.0%) after the first and second doses, respectively. No Grade 4 side effects occurred. The second dose had significantly more side effects than the first dose (p < 0.001). Side effects occurred after the second dose in 571 female (92.1%) and 178 male participants (80.1%). Female participants had a higher incidence of side effects than the male participants (p < 0.001). A comparison among the age groups showed significant differences (p = 0.018), and the frequency of side effects decreased with age. Twenty-three individuals participated in the survey of antibody titer transition. After the second vaccine dose, the median antibody titers for IgG and IgM were 3.76 and 0.07 AU/mL, respectively. Both IgG and IgM titers showed a significant increase over the study period (p < 0.001). Conclusions The BNT162b2 mRNA COVID-19 vaccine might be safe for Japanese people, and the antibody titer increased with two doses of vaccination. Larger nationwide studies are warranted to verify these findings.

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“…Most seroprevalence studies performed in other settings have included specific high-risk groups or randomly-selected participants which exclude certain population groups, such as ill or quarantined people, or institutionalized individuals, among others [11] , [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] . Thus, their results might not accurately reflect the actual seroprevalence in the population.…”

Section: Introductionmentioning

confidence: 99%

Mass SARS-CoV-2 serological screening, a population-based study in the Principality of Andorra

Royo-Cebrecos

Vilanova

López

et al. 2021

The Lancet Regional Health - Europe

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Background Andorra is a small country located in the Pyrenees attracting millions of visitors for tourism, mostly associated with skiing, and nature-related activities. As its neighbouring countries, Spain and France, it has been heavily affected by the COVID-19 pandemic. We estimated SARS-CoV-2 seroprevalence in the entire country by universal serological testing under a lockdown environment. Methods A total of 77,543 inhabitants of Andorra were invited to participate in the study. From 4-28 May, 2020, two cross sectional serological surveys were conducted using a rapid serological test (nCOV IgG/IgM) on a finger prick blood sample in 59 drive-through or walk-through checkpoints, all over Andorra. We calculated seroprevalence of antibodies against SARS-CoV-2 and analysed the main sociodemographic factors associated with being seropositive. Findings 70,494 inhabitants (90.9% of the population) participated in at least one survey. Overall seroprevalence was 11.0%. The most affected age groups were those over 90 years old (15.2%) and 80-89 (13.8%), followed by adults 50-59 (13.6%) and adolescents 10-19 (13.7%). Most seropositive participants, 6,061 (95.1%), were asymptomatic before the surveys. The multivariable analysis showed that the odds of being seropositive was higher among seasonal workers (OR 2.41; 95% CI 1.07-5.45) or in the population living in La Massana region, a popular ski-related area (OR 2.66; 95% CI 2.44-2.89). A higher seroprevalence was observed in those familiar nuclei with greater numbers of cohabitants: 18% in families with 6 household members or more; 13% in medium size families (3/4/5 people) and 12% in small size (1 to 2 people) nuclei. Interpretation The prevalence of antibodies against SARS-CoV-2 in the population of Andorra was high during the first wave of the pandemic. Seasonal workers and inhabitants based in La Massana presented a higher seroprevalence. Mass antibody screening allows to identify infection hotspots and should contribute to the design of tailored interventions to prevent SARS-CoV-2 transmission in Andorra. Funding Andorran Ministry of Health, Andorran Health Services.

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Prevalence of SARS-CoV-2–Specific Antibodies, Japan, June 2020

Cited by 30 publications

References 8 publications

Serological testing reveals the hidden COVID-19 burden among healthcare workers experiencing a SARS-CoV-2 nosocomial outbreak

Serological testing reveals the hidden COVID-19 burden among healthcare workers experiencing a SARS-CoV-2 nosocomial outbreak

Side effects and antibody titer transition of the BNT162b2 messenger ribonucleic acid coronavirus disease 2019 vaccine in Japan

Mass SARS-CoV-2 serological screening, a population-based study in the Principality of Andorra

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