Variant-specific IgA protects against Omicron infection.

BACKGROUND: The emergence of rapidly evolving SARS-CoV-2 variants, coupled with waning vaccine-induced immunity, has contributed to the rise of vaccine breakthrough infections. It is crucial to understand how vaccine-induced protection is mediated. METHODS: We examined two prospective cohorts of mRNA-vaccinated-and-boosted individuals during the Omicron wave of infection in Singapore. RESULTS: We found that, individuals, who remain uninfected over the follow-up period, had a higher variant-specific IgA, but not IgG, antibody response at 1-month post booster vaccination, compared with individuals who became infected. CONCLUSIONS: We conclude that IgA may have a potential contributory role in protection against Omicron infection.

What does the anesthesiologist need to know about monkeypox?

PURPOSE: Monkeypox (or "mpox" as preferred by the World Health Organization) is an emerging infectious disease with sustained global transmission occurring outside of West Africa and the Democratic Republic of Congo. The recent 2022 mpox outbreak has involved widespread atypical presentations. Infected patients requiring surgery can increase the exposure of health care professionals and other patients to the virus. As it is a relatively new infectious disease internationally, there is less familiarity in managing this risk, especially in the surgical and anesthesia setting. This paper aims to provide information about mpox and how to manage suspected or confirmed cases. SOURCE: Various authorities such as the World Health Organization, Infection Prevention and Control Canada, Public Health Agency of Canada, the Centers for Disease Control and Prevention (USA), and the National Centre for Infectious Diseases (Singapore) have recommended that public health and hospital systems prepare to recognize, isolate, and care for suspected and confirmed cases appropriately, as well as manage any possible exposure of staff and patients. PRINCIPAL FINDINGS: Local authorities and hospitals should set up protocols for health care providers (HCPs) to minimize nosocomial transmission and risk to HCPs. Antivirals used in patients with more severe disease may cause renal or hepatic impairment and thus anesthetic drug pharmacology. Anesthesiologists and surgeons should be able to recognize mpox, and work with local infection control and epidemiologic programs to familiarize themselves with relevant infection prevention guidelines. CONCLUSION: Essential measures include clear protocols for transferring and managing surgical patients who are suspected or confirmed to be infected with the virus. Care in use of personal protective equipment and handling contaminated material is necessary to prevent inadvertent exposure. Risk stratification after exposure should be done to determine need for post-exposure prophylaxis for staff.

RéSUMé: OBJECTIF: La variole du singe (ou « mpox ¼, le terme privilégié en anglais par l'Organisation mondiale de la santé) est une maladie infectieuse émergente dont la transmission mondiale est soutenue en dehors de l'Afrique de l'Ouest et de la République démocratique du Congo. La récente épidémie de variole du singe de 2022 a donné lieu à des présentations atypiques généralisées. Les patients infectés nécessitant une intervention chirurgicale peuvent accroître l'exposition des professionnels de la santé et des autres patients au virus. Comme il s'agit d'une maladie infectieuse relativement nouvelle à l'échelle internationale, la gestion de ce risque d'exposition est moins familière, en particulier dans le cadre chirurgical et anesthésique. Cet article vise à fournir des informations sur la variole du singe et sur la prise en charge des cas suspects ou confirmés. SOURCES: Diverses autorités telles que l'Organisation mondiale de la Santé, Prévention et contrôle des infections Canada, l'Agence de la santé publique du Canada, les Centers for Disease Control and Prevention (États-Unis) et le National Centre for Infectious Diseases (Singapour) ont recommandé que les systèmes de santé publique et hospitaliers se préparent à reconnaître, isoler et soigner les cas suspects et confirmés de manière appropriée, ainsi qu'à gérer toute exposition possible du personnel et des patients. CONSTATATIONS PRINCIPALES: Les autorités locales et les hôpitaux devraient établir des protocoles pour les fournisseurs de soins de santé afin de minimiser la transmission nosocomiale et les risques pour eux. Les antiviraux utilisés chez les patients atteints d'une forme plus grave de la maladie peuvent entraîner une insuffisance rénale ou hépatique et, par conséquent, une altération de la pharmacologie anesthésique. Les anesthésiologistes et les chirurgiens devraient être en mesure de reconnaître la variole du singe et de travailler avec les programmes locaux de contrôle des infections et d'épidémiologie pour se familiariser avec les lignes directrices pertinentes en matière de prévention des infections. CONCLUSION: Les mesures essentielles comprennent des protocoles clairs pour le transfert et la prise en charge des patients chirurgicaux soupçonnés ou confirmés d'être infectés par le virus. Il faut faire preuve de prudence dans l'utilisation des équipements de protection individuelle et la manipulation des matières contaminées afin de prévenir une exposition accidentelle. La stratification du risque après l'exposition devrait être réalisée afin de déterminer la nécessité d'une prophylaxie post-exposition pour le personnel.

The COVOSMIA-19 trial: Preliminary application of the Singapore smell and taste test to objectively measure smell and taste function with COVID-19.

Sudden loss of smell and/or taste has been identified as an early symptom of SARS-CoV-2 2019 (COVID-19) infection, and presents an effective target for prompt self-isolation and reducing community spread. The current study sought to develop and test a novel, rapid, self-administered test to objectively measure smell and taste losses associated with COVID-19, and administered self-report questionnaires to characterise symptoms associated with COVID-19 in Singapore. Participants (N = 99) completed questionnaires to record recent changes in smell and taste ability. This was followed by the 'Singapore Smell and Taste Test' (SSTT), a personal, objective testing kit for daily self-assessment of smell and taste function at their place of residence. Seventy-two recruited participants were confirmed as COVID-19 positive at baseline, of which 58 completed the SSTT at home. Of these, 36.2% had objectively measured smell and/or taste loss. The SSTT measures of smell and taste function were positively associated with participants' self-reported smell and taste acuity, and rated smell intensity of 6 common household items. This study presents the first application of the SSTT as a rapid, cost-effective, objective tool to self-monitor smell and taste function in a residential setting, and ensures comparability across individuals through the use of standardised stimuli. The SSTT has potential for future application in populations with limited access to formal COVID-19 testing as a self-administered objective method to monitor sudden changes in smell and taste, and to prompt early self-isolation, in order to reduce community transmission of COVID-19.

Establishing a New Normal for Hospital Care: A Whole of Hospital Approach to Coronavirus Disease 2019 (COVID-19).

Singapore's hospitals had prepared to receive patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), planning various scenarios and levels of surge with a policy of isolating all confirmed cases as inpatients. The National University Hospital adopted a whole of hospital approach to coronavirus disease 2019 (COVID-19) with 3 primary goals: zero hospital-acquired COVID-19, all patients receive timely necessary care, and maintenance of staff morale. These goals to date have been met. A large influx of COVID-19 cases required significant transformation of clinical and operational processes. Isolation room numbers almost tripled and dedicated COVID-19 cohort wards were established, elective care was postponed, and intensive care units were augmented with equipment and manpower. In the wake of the surge, establishing a new normal for hospital care requires maintaining vigilance to detect endemic COVID-19, establishing contingency plans to ramp up in case of another surge, while returning to business as usual.

Responding to COVID-19: how an academic infectious diseases division mobilized in Singapore.

BACKGROUND: On January 30, COVID-19 was declared a Public Health Emergency of International Concern-a week after Singapore's first imported case and 5 days before local transmission. The National University Hospital (NUH) is Singapore's third largest hospital with 1200 beds, heavy clinical workloads, and major roles in research and teaching. MAIN BODY: With memories of SARS still vivid, there was an urgent requirement for the NUH Division of Infectious Diseases to adapt-undergoing major reorganization to face rapidly changing priorities while ensuring usual essential services and standards. Leveraging on individual strengths, our division mobilized to meet the demands of COVID-19 while engaging in high-level coordination, strategy, and advocacy. We present our experience of the 60 days since the nation's first case. During this time, our hospital has managed 3030 suspect cases, including 1300 inpatients, 37 confirmed cases, and overseen 4384 samples tested for COVID-19. CONCLUSION: Complex hospital adaptations were supported by an unprecedented number of workflows and coordination channels essential to safe and effective operations. The actions we describe, aligned with international recommendations and emerging evidence-based best practices, may serve as a framework for other divisions and institutions facing the spread of COVID-19 globally.

ELSA recommendations for minimally invasive surgery during a community spread pandemic: a centered approach in Asia from widespread to recovery phases.

BACKGROUND: The COVID-19 pandemic has resulted in significant changes to surgical practice across the worlds. Some countries are seeing a tailing down of cases, while others are still having persistent and sustained community spread. These evolving disease patterns call for a customized and dynamic approach to the selection, screening, planning, and for the conduct of surgery for these patients. METHODS: The current literature and various international society guidelines were reviewed and a set of recommendations were drafted. These were circulated to the Governors of the Endoscopic and Laparoscopic Surgeons of Asia (ELSA) for expert comments and discussion. The results of these were compiled and are presented in this paper. RESULTS: The recommendations include guidance for selection and screening of patients in times of active community spread, limited community spread, during times of sporadic cases or recovery and the transition between phases. Personal protective equipment requirements are also reviewed for each phase as minimum requirements. Capability management for the re-opening of services is also discussed. The choice between open and laparoscopic surgery is patient based, and the relative advantages of laparoscopic surgery with regard to complications, and respiratory recovery after major surgery has to be weighed against the lack of safety data for laparoscopic surgery in COVID-19 positive patients. We provide recommendations on the operating room set up and conduct of general surgery. If laparoscopic surgery is to be performed, we describe circuit modifications to assist in reducing plume generation and aerosolization. CONCLUSION: The COVID-19 pandemic requires every surgical unit to have clear guidelines to ensure both patient and staff safety. These guidelines may assist in providing guidance to units developing their own protocols. A judicious approach must be adopted as surgical units look to re-open services as the pandemic evolves.

Does Prior Respiratory Viral Infection Provide Cross-Protection Against Subsequent Respiratory Viral Infections? A Systematic Review and Meta-Analysis.

The epidemiology of different respiratory viral infections is believed to be affected by prior viral infections in addition to seasonal effects. This PROSPERO-registered systematic review identified 7388 studies, of which six met our criteria to answer the question specifically. The purpose of this review was to compare the prevalence of sequential viral infections in those with previously documented positive versus negative swabs. The pooled prevalence of sequential viral infections over varying periods from 30-1000 days of follow-up was higher following a negative respiratory viral swab at 0.15 than following a positive swab at 0.08, indicating the potential protective effects of prior respiratory viral infections. However, significant heterogeneity and publication biases were noted. There is some evidence, albeit of low quality, of a possible protective effect of an initial viral infection against subsequent infections by a different virus, which is possibly due to broad, nonspecific innate immunity. Future prospective studies are needed to validate our findings.

Longitudinal single cell atlas identifies complex temporal relationship between type I interferon response and COVID-19 severity.

Due to the paucity of longitudinal molecular studies of COVID-19, particularly those covering the early stages of infection (Days 1-8 symptom onset), our understanding of host response over the disease course is limited. We perform longitudinal single cell RNA-seq on 286 blood samples from 108 age- and sex-matched COVID-19 patients, including 73 with early samples. We examine discrete cell subtypes and continuous cell states longitudinally, and we identify upregulation of type I IFN-stimulated genes (ISGs) as the predominant early signature of subsequent worsening of symptoms, which we validate in an independent cohort and corroborate by plasma markers. However, ISG expression is dynamic in progressors, spiking early and then rapidly receding to the level of severity-matched non-progressors. In contrast, cross-sectional analysis shows that ISG expression is deficient and IFN suppressors such as SOCS3 are upregulated in severe and critical COVID-19. We validate the latter in four independent cohorts, and SOCS3 inhibition reduces SARS-CoV-2 replication in vitro. In summary, we identify complexity in type I IFN response to COVID-19, as well as a potential avenue for host-directed therapy.

Antibiotic utilisation and resistance over the first decade of nationally funded antimicrobial stewardship programmes in Singapore acute-care hospitals.

OBJECTIVE: The aim of this study was to describe the time series of broad-spectrum antibiotic utilisation and incidence of antibiotic-resistant organisms during the implementation of antimicrobial stewardship programmes (ASP) in Singapore. METHODS: An observational study was conducted using data from 2011 to 2020 in seven acute-care public hospitals. We applied joinpoint regressions to investigate changes in antibiotic utilisation rate and incidence density of antibiotic-resistant organisms. RESULTS: Across the seven hospitals, quarterly broad-spectrum antibiotic utilisation rate remained stable. Half-yearly incidence density of antibiotic-resistant organisms with two joinpoints at first half (H1) of 2012 and second half (H2) of 2014 decreased significantly in the second and third period with a half-yearly percentage change (HPC) of -2.9% and - 0.5%, respectively. Across the five hospitals with complete data, half-yearly broad-spectrum antibiotic utilisation rate with one joinpoint decreased significantly from H1 of 2011 to H2 of 2018 (HPC - 4.0%) and H2 of 2018 to H2 2020 (HPC - 0.5%). Incidence density of antibiotic-resistant organisms decreased significantly in the two joinpoint periods from H1 of 2012 to H2 of 2014 (HPC - 2.7%) and H2 of 2014 to H2 of 2020 (HPC - 1.0%). Ceftriaxone with one joinpoint decreased significantly from H1 of 2011 to H1 of 2014 (HPC - 6.0%) and H1 of 2014 to H2 of 2020 (HPC - 1.8%) and ceftriaxone-resistant E. coli and K. pneumoniae decreased significantly in later periods, from H2 of 2016 to H2 of 2020 (HPC - 2.5%) and H1 of 2012 to H2 of 2015 (HPC - 4.6%) respectively. Anti-pseudomonal antibiotics with one joinpoint decreased significantly from H1 of 2011 to H2 of 2014 (HPC - 4.5%) and H2 of 2014 to H2 of 2020 (HPC - 0.8%) and that of quinolones with one joinpoint at H1 of 2015 decreased significantly in the first period. C. difficile with one joinpoint increased significantly from H1 of 2011 to H1 of 2015 (HPC 3.9%) and decreased significantly from H1 of 2015 to H2 of 2020 (HPC - 4.9%). CONCLUSIONS: In the five hospitals with complete data, decrease in broad-spectrum antibiotic utilisation rate was followed by decrease in incidence density of antibiotic-resistant organisms. ASP should continue to be nationally funded as a key measure to combat antimicrobial resistance in acute care hospitals.

Employment of a high throughput functional assay to define the critical factors that influence vaccine induced cross-variant neutralizing antibodies for SARS-CoV-2.

The scale and duration of neutralizing antibody responses targeting SARS-CoV-2 viral variants represents a critically important serological parameter that predicts protective immunity for COVID-19. In this study, we describe the development and employment of a new functional assay that measures neutralizing antibodies for SARS-CoV-2 and present longitudinal data illustrating the impact of age, sex and comorbidities on the kinetics and strength of vaccine-induced antibody responses for key variants in an Asian volunteer cohort. We also present an accurate quantitation of serological responses for SARS-CoV-2 that exploits a unique set of in-house, recombinant human monoclonal antibodies targeting the viral Spike and nucleocapsid proteins and demonstrate a reduction in neutralizing antibody titres across all groups 6 months post-vaccination. We also observe a marked reduction in the serological binding activity and neutralizing responses targeting recently newly emerged Omicron variants including XBB 1.5 and highlight a significant increase in cross-protective neutralizing antibody responses following a third dose (boost) of vaccine. These data illustrate how key virological factors such as immune escape mutations combined with host demographic factors such as age and sex of the vaccinated individual influence the strength and duration of cross-protective serological immunity for COVID-19.

Clinical Course, Immunogenicity, and Efficacy of BNT162b2 mRNA Vaccination Against SARS-CoV-2 Infection in Liver Transplant Recipients.

Background: Immunocompromised individuals have been excluded from landmark studies of messenger RNA vaccinations for severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2). In such patients, the response to vaccination may be blunted and may wane more quickly compared with immunocompetent patients. We studied the factors associated with decreased antibody response to SARS-CoV-2 vaccination and risk factors for subsequent breakthrough infections in liver transplant (LT) patients undergoing coronavirus disease 2019 vaccination with at least 2 doses of messenger RNA vaccine from April 28, 2021, to April 28, 2022. Methods: All LT recipients received at least 2 doses of the BNT162b2 (Pfizer BioNTech) vaccine 21 d apart. We measured the antibody response against the SARS-CoV-2 spike protein using the Roche Elecsys immunoassay to the receptor-binding domain of the SARS-CoV-2 spike protein, and the presence of neutralizing antibodies was measured by the surrogate virus neutralization test (cPass) before first and second doses of vaccination and also between 2 and 3 mo after the second dose of vaccination. Results: Ninety-three LT recipients who received 2 doses of BNT162b2 were included in the analysis. The mean time from LT was 110 ± 154 mo. After 2-dose vaccination, 38.7% of LT recipients (36/93) were vaccine nonresponders on the cPass assay compared with 20.4% (19/93) on the Roche S assay. On multivariable analysis, increased age and increased tacrolimus trough were found to be associated with poor neutralizing antibody response (P = 0.038 and 0.022, respectively). The use of antimetabolite therapy in conjunction with tacrolimus approached statistical significance (odds ratio 0.21; 95% confidence interval, 0.180-3.72; P = 0.062). Breakthrough infection occurred in 18 of 88 LT recipients (20.4%). Female gender was independently associated with breakthrough infections (P < 0.001). Conclusions: Among LT recipients, older age and higher tacrolimus trough levels were associated with poorer immune response to 2-dose SARS-CoV-2 vaccination. Further studies are needed to assess variables associated with breakthrough infections and, hence, who should be prioritized for booster vaccination.

Myopericarditis following COVID-19 vaccination and non-COVID-19 vaccination: a systematic review and meta-analysis.

BACKGROUND: Myopericarditis is a rare complication of vaccination. However, there have been increasing reports of myopericarditis following COVID-19 vaccination, especially among adolescents and young adults. We aimed to characterise the incidence of myopericarditis following COVID-19 vaccination, and compare this with non-COVID-19 vaccination. METHODS: We did a systematic review and meta-analysis, searching four international databases from Jan 1, 1947, to Dec 31, 2021, for studies in English reporting on the incidence of myopericarditis following vaccination (the primary outcome). We included studies reporting on people in the general population who had myopericarditis in temporal relation to receiving vaccines, and excluded studies on a specific subpopulation of patients, non-human studies, and studies in which the number of doses was not reported. Random-effects meta-analyses (DerSimonian and Laird) were conducted, and the intra-study risk of bias (Joanna Briggs Institute checklist) and certainty of evidence (Grading of Recommendations, Assessment, Development and Evaluations approach) were assessed. We analysed the difference in incidence of myopericarditis among subpopulations, stratifying by the type of vaccine (COVID-19 vs non-COVID-19) and age group (adult vs paediatric). Among COVID-19 vaccinations, we examined the effect of the type of vaccine (mRNA or non-mRNA), sex, age, and dose on the incidence of myopericarditis. This study was registered with PROSPERO (CRD42021275477). FINDINGS: The overall incidence of myopericarditis from 22 studies (405 272 721 vaccine doses) was 33·3 cases (95% CI 15·3-72·6) per million vaccine doses, and did not differ significantly between people who received COVID-19 vaccines (18·2 [10·9-30·3], 11 studies [395 361 933 doses], high certainty) and those who received non-COVID-19 vaccines (56·0 [10·7-293·7], 11 studies [9 910 788 doses], moderate certainty, p=0·20). Compared with COVID-19 vaccination, the incidence of myopericarditis was significantly higher following smallpox vaccinations (132·1 [81·3-214·6], p<0·0001) but was not significantly different after influenza vaccinations (1·3 [0·0-884·1], p=0·43) or in studies reporting on various other non-smallpox vaccinations (57·0 [1·1-3036·6], p=0·58). Among people who received COVID-19 vaccines, the incidence of myopericarditis was significantly higher in males (vs females), in people younger than 30 years (vs 30 years or older), after receiving an mRNA vaccine (vs non-mRNA vaccine), and after a second dose of vaccine (vs a first or third dose). INTERPRETATION: The overall risk of myopericarditis after receiving a COVID-19 vaccine is low. However, younger males have an increased incidence of myopericarditis, particularly after receiving mRNA vaccines. Nevertheless, the risks of such rare adverse events should be balanced against the risks of COVID-19 infection (including myopericarditis). FUNDING: None.

Role of Occupational Health Services in Planning and Implementing of Staff COVID-19 Vaccination Clinic: A Tertiary Hospital Experience in Singapore.

CONTEXT: Healthcare workers all over the world were prioritized for vaccination against COVID-19 in view of the high-risk nature of their job scopes when vaccines were first available in late 2020. Vaccine hesitancy was an important problem to tackle in order to achieve a high vaccination rate, especially for vaccines that were developed using mRNA technology. We aimed to use the '3Cs' model to address vaccine hesitancy to ensure maximal uptake of the Pfizer-BioNTech vaccine among healthcare workers in a tertiary hospital in Singapore. METHODS: Various measures were used to reduce the confidence, complacency, and convenience barriers. The staff vaccination clinic was on-site and centralized, with appointments given in advance to ensure vaccine availability and to reduce wait time, providing convenience to staff. Direct and repeated communications with the staff via multiple channels were used to address vaccine safety and efficacy so as to promote confidence in the vaccines and overcome complacency barriers. To further encourage staff to get vaccinated, staff were allowed time off for vaccination when at work. Staff with a high risk of exposure to COVID-19 or those caring for immunocompromised patients were prioritized to take the vaccines first. The collection of data on adverse events was via on-site monitoring and consultation at Occupational Health Clinic (OHC). RESULTS: Nearly 80% of staff had completed vaccination when the vaccination exercise ended at the end of March 2021. With the loosening of the contraindications to vaccination over time, staff vaccination rates reached 89.3% in early July and nearly 99.9% by the end of the year. No major or serious vaccine-related medication or administration errors were reported. No staff had anaphylaxis. CONCLUSIONS: By using the '3Cs' model to plan out the vaccination exercise, it is possible to achieve a high vaccination rate coupled with effective and customized communications. This multi-disciplinary team approach can be adapted to guide vaccination efforts in various settings in future pandemics.

Detection of hospital environmental contamination during SARS-CoV-2 Omicron predominance using a highly sensitive air sampling device.

Background and objectives: The high transmissibility of SARS-CoV-2 has exposed weaknesses in our infection control and detection measures, particularly in healthcare settings. Aerial sampling has evolved from passive impact filters to active sampling using negative pressure to expose culture substrate for virus detection. We evaluated the effectiveness of an active air sampling device as a potential surveillance system in detecting hospital pathogens, for augmenting containment measures to prevent nosocomial transmission, using SARS-CoV-2 as a surrogate. Methods: We conducted air sampling in a hospital environment using the AerosolSenseTM air sampling device and compared it with surface swabs for their capacity to detect SARS-CoV-2. Results: When combined with RT-qPCR detection, we found the device provided consistent SARS-CoV-2 detection, compared to surface sampling, in as little as 2 h of sampling time. The device also showed that it can identify minute quantities of SARS-CoV-2 in designated "clean areas" and through a N95 mask, indicating good surveillance capacity and sensitivity of the device in hospital settings. Conclusion: Active air sampling was shown to be a sensitive surveillance system in healthcare settings. Findings from this study can also be applied in an organism agnostic manner for surveillance in the hospital, improving our ability to contain and prevent nosocomial outbreaks.

Rapid Evaluation of Vaccine Booster Effectiveness against SARS-CoV-2 Variants.

As the COVID-19 pandemic continues, countries around the world are switching toward vaccinations and boosters to combat the pandemic. However, waning immunity against SARS-CoV-2 wild-type (WT) and variants have been widely reported. Booster vaccinations have shown to be able to increase immunological protection against new variants; however, the protection observed appears to decrease quickly over time suggesting a second booster shot may be appropriate. Moreover, heterogeneity and waning of the immune response at the individual level was observed suggesting a more personalized vaccination approach should be considered. To evaluate such a personalized strategy, it is important to have the ability to rapidly evaluate the level of neutralizing antibody (nAbs) response against variants at the individual level and ideally at a point of care setting. Here, we applied the recently developed cellulose pulled-down virus neutralization test (cpVNT) to rapidly assess individual nAb levels to WT and variants of concerns in response to booster vaccination. Our findings confirmed significant heterogeneity of nAb responses against a panel of SARS-CoV-2 variants, and indicated a strong increase in nAb response against variants of concern (VOCs) upon booster vaccination. For instance, the nAb response against current predominant omicron variant was observed with medians of 88.1% (n = 6, 95% CI = 73.2% to 96.2%) within 1-month postbooster and 70.7% (n = 22, 95% CI = 66.4% to 81.8%) 3 months postbooster. Our data show a point of care (POC) test focusing on nAb response levels against VOCs can guide decisions on the potential need for booster vaccinations at individual level. Importantly, it also suggests the current booster vaccines only give a transient protective response against some VOC and new more targeted formulations of a booster vaccine against specific VOC may need to be developed in the future. IMPORTANCE Vaccination against SARS-CoV-2 induces protection through production of neutralization antibodies (nAb). The level of nAb is a major indicator of immunity against SARS-CoV-2 infection. We developed a rapid point-of-care test that can monitor the nAb level from a drop of finger stick blood. Here, we have implemented the test to monitor individual nAb level against wild-type and variants of SARS-CoV-2 at various time points of vaccination, including post-second-dose vaccination and postbooster vaccination. Huge diversity of nAb levels were observed among individuals as well as increment in nAb levels especially against Omicron variant after booster vaccination. This study evaluated the performance of this point-of-care test for personalized nAb response tracking. It verifies the potential of using a rapid nAb test to guide future vaccination regimens at both the individual and population level.

Finger stick blood test to assess postvaccination SARS-CoV-2 neutralizing antibody response against variants.

There is clinical need for a quantifiable point-of-care (PoC) SARS-CoV-2 neutralizing antibody (nAb) test that is adaptable with the pandemic's changing landscape. Here, we present a rapid and semi-quantitative nAb test that uses finger stick or venous blood to assess the nAb response of vaccinated population against wild-type (WT), alpha, beta, gamma, and delta variant RBDs. It captures a clinically relevant range of nAb levels, and effectively differentiates prevaccination, post first dose, and post second dose vaccination samples within 10 min. The data observed against alpha, beta, gamma, and delta variants agrees with published results evaluated in established serology tests. Finally, our test revealed a substantial reduction in nAb level for beta, gamma, and delta variants between early BNT162b2 vaccination group (within 3 months) and later vaccination group (post 3 months). This test is highly suited for PoC settings and provides an insightful nAb response in a postvaccinated population.