Serological and Community Awareness Study of Lumpy Skin Disease in Different Agro-Ecological Zones of Sidama Regional State, Southern Ethiopia.

The lumpy skin disease (LSD) vaccination status and epidemiological distribution remain unknown in some parts of Ethiopia, including the Sidama regional state. In this study, a serological survey of LSD was performed using a specific virus neutralization assay in selected districts of the Sidama regional state representing three agroecological zones from September 2021 to June 2022. Moreover, an assessment of community awareness and LSD vaccine-related problems was conducted using a questionnaire. Our results showed an overall animal and herd level seroprevalence of 40.8% (95%CI = 35.8, 45.8) and 81% (95%CI = 77, 85), respectively. High and low seroprevalence were observed in lowland (48%) and highland (28%) areas, although they were not statistically significant. However, risk factors such as management systems and breeds showed substantial differences in their LSD prevalence. The results obtained through the questionnaire showed that a small portion of respondents (29.2%) know about LSD and vaccinate their cattle (23.3%) against this disease. Only 20.8% of the respondents stated that there was LSD occurrence in their vaccinated cattle. In conclusion, both qualitative and quantitative study results showed the need for intervention in terms of community-based awareness creation about LSD clinical signs and vaccination advantages together with the frequently updated information on LSD prevalence.

Raising Epidemiological Awareness: Assessment of Measles/MMR Susceptibility in Highly Vaccinated Clusters within the Hungarian and Croatian Population-A Sero-Surveillance Analysis.

Perceptions of the complete eradication of vaccine-preventable diseases such as measles, mumps, and rubella (MMR) may foster complacency and compromise vaccination efforts. Decreased measles vaccination rates during the COVID-19 pandemic have heightened the risk of outbreaks, even in adequately vaccinated populations. To address this, we have aligned with ECDC recommendations, leveraging previous cross-border sero-epidemiological assessments between Pécs, Hungary, and Osijek, Croatia, to identify latent risk groups and uncover potential parallels between our nations. Testing 2680 Hungarian and 1764 Croatian serum samples for anti-MMR IgG via ELISAs revealed anti-measles seropositivity ratios below expectations in Croatian cohorts aged ~20-30 (75.7%), ~30-40 (77.5%) and ~40-50 years (73.3%). Similarly, Hungarian samples also showed suboptimal seropositivity ratios in the ~30-40 (80.9%) and ~40-50 (87.3%) age groups. Considering mumps- and rubella-associated seropositivity trends, in both examined populations, individuals aged ~30-50 years exhibited the highest vulnerability. Additionally, we noted congruent seropositivity trends across both countries, despite distinct immunization and epidemiological contexts. Therefore, we propose expanding research to encompass the intricate dynamics of vaccination, including waning long-term immunity. This understanding could facilitate targeted interventions and bolster public awareness. Our findings underscore persistent challenges in attaining robust immunity against measles despite vaccination endeavors.

Seroprevalence of measles antibodies in the Italian general population in 2019-2020.

In Italy, the measles elimination target has not yet been reached despite a significant reduction in cases. A multicenter study was conducted to estimate the prevalence of anti-measles (MV) IgG antibodies in the Italian population by age, sex and geographical area. To determine the level of MV-specific antibodies in sera, the immunoenzymatic assay ELISA was used (Enzygnost Anti-VZV/IgG, Siemens Healthcare Diagnostic Products GmbH, Germany). Overall, 3746 serum samples collected in the years 2019-20 from healthy subjects aged 6-64 years residing in 13 Italian regions. The overall seroprevalence of anti-MV IgG was 91.2 % (90.6 % male, 91.7 % female). Significantly higher seroprevalence values (p < 0.05) were recorded for the extreme age groups of the study population (6-9 years: 94.2 %; 40-64 years: 97.6 %). Subjects 20-39 and 40-64 years old had significantly higher antibody titers suggesting a protection against measles mainly derived from natural infection. Seroprevalence was significantly higher in the South (93.2 %) than in the Northern-Central Italy (88.9 %). The results indicate an increase in the overall seroprevalence data compared to previous investigations. However, further efforts must be made to implement and maintain high measles vaccination coverage to avoid the risk of future epidemic outbreaks.

Seroprotection against tetanus in the Italian general population.

BACKGROUND: Tetanus is a non-communicable disease, preventable with vaccination. Despite the implemented vaccination strategy, a certain number of tetanus cases per year continue to occur. The aim of the study was to evaluate the seroprevalence of anti-tetanus antibodies in the Italian population by age, sex and geographical area. METHODS: To determine the level of tetanus-specific antibodies, an immunoenzymatic assay was used. RESULTS: A total of 3,821 serum samples were collected in the years 2019-20 from healthy subjects aged 6-90 years residing in 13 Italian regions. Overall, 85 % of the tested subjects resulted positive. The rate of subjects protected against tetanus showed a gradual decrease from the younger age groups to the older ones (6-12 years: 93.6 %, 13-24 years: 91.8 %, 25-39 years: 91.0 %, 40-64 years: 78.2 %, ≥ 65 years: 45.3 %); this is particularly evident in the Southern regions and Islands. Moreover, the prevalence of subjects with low protection (<0.1 IU/ml) was significantly higher in the ≥ 65 age group (10.3 %). Males and females' prevalence showed a significant difference only in the oldest age group (M: 60.8 %, F: 30.4 %). In general, a higher prevalence was observed for Northern (90.8 %) and Central regions (87.3 %) than Southern regions and Islands (80.0 %). CONCLUSION: These data, compared with epidemiological ones which showed a high number of cases in the elderly, confirmed that the population with lower protection has a greater risk of contracting the disease, demonstrating the need for adequate immunization through both primary vaccination and boosters for all ages and both sexes, in order to provide lifelong protection.

Identification of associated risk factors for serological distribution of hepatitis B virus via machine learning models.

BACKGROUND: The provincial-level sero-survey was launched to learn the updated seroprevalence of hepatitis B virus (HBV) infection in the general population aged 1-69 years in Chongqing and to assess the risk factors for HBV infection to effectively screen persons with chronic hepatitis B (CHB). METHODS: A total of 1828 individuals aged 1-69 years were investigated, and hepatitis B surface antigen (HBsAg), antibody to HBsAg (HBsAb), and antibody to B core antigen (HBcAb) were detected. Logistic regression and three machine learning (ML) algorithms, including random forest (RF), support vector machine (SVM), and stochastic gradient boosting (SGB), were developed for analysis. RESULTS: The HBsAg prevalence of the total population was 3.83%, and among persons aged 1-14 years and 15-69 years, it was 0.24% and 4.89%, respectively. A large figure of 95.18% (770/809) of adults was unaware of their occult HBV infection. Age, region, and immunization history were found to be statistically associated with HBcAb prevalence with a logistic regression model. The prediction accuracies were 0.717, 0.727, and 0.725 for the proposed RF, SVM, and SGB models, respectively. CONCLUSIONS: The logistic regression integrated with ML models could helpfully screen the risk factors for HBV infection and identify high-risk populations with CHB.

Equine influenza outbreak in Eastern of Algeria in 2021: The first introduction of Florida Clade 1 to Maghreb area.

We have performed an equine influenza (EI) serological study of the equine population in Algeria by testing 298 serum samples collected between February and August 2021 from 5 provinces. The results were obtained performing an NP-ELISA. Our results revealed that 49.3% (147/298) samples positive for antibodies to EI (H3N8). During this study and after a gap of one decade an outbreak of EI was reported in Algeria in the first week of March 2021. The disease was confirmed by virus detection from the nasal swabs (n = 39) by qRT-PCR and by identifying 5 EI seroconversion. The virus sequences were identified as H3N8 by sequencing the haemagglutinin (HA) and neuraminidase (NA) genes. Alignment of HA1 amino acid sequence confirmed that viruses belong to Clade 1 of the Florida sublineage in the American lineage. This study indicate the first detection of FC1 strain of EIV in Maghreb area.

Immunity of Canadians and risk of epidemics workshop - Conference report.

On November 18-19, 2019, the Immunity of Canadians and Risk of Epidemics (iCARE) Network convened a workshop in Toronto, Ontario, Canada. The objectives of the workshop were to raise the profile of sero-epidemiology in Canada, discuss best practice and methodological innovations, and strategize on the future direction of sero-epidemiology work in Canada. In this conference report, we describe the presentations and discussions from the workshop, and comment on the impact of the COVID-19 pandemic on serosurveillance initiatives, both in Canada and abroad.

Point of care detection of SARS-CoV-2 antibodies and neutralisation capacity-lateral flow immunoassay evaluation compared to commercial assay to inform potential role in therapeutic and surveillance practices.

Introduction: As the COVID-19 pandemic moves towards endemic status, testing strategies are being de-escalated. A rapid and effective point of care test (POCT) assessment of SARS-CoV-2 immune responses can inform clinical decision-making and epidemiological monitoring of the disease. This cross-sectional seroprevalence study of anti-SARS-CoV-2 antibodies in Irish healthcare workers assessed how rapid anti-SARS-CoV-2 antibody testing can be compared to a standard laboratory assay, discusses its effectiveness in neutralisation assessment and its uses into the future of the pandemic. Methods: A point of care lateral flow immunoassay (LFA) detecting anti-SARS-CoV-2 spike (S)-receptor binding domain (RBD) neutralising antibodies (Healgen SARS-CoV-2 neutralising Antibody Rapid Test Cassette) was compared to the Roche Elecsys/-S anti-SARS-CoV-2 antibody assays and an in vitro surrogate neutralisation assay. A correlation between anti-spike (S), anti-nucleocapsid (N) titres, and in vitro neutralisation was also assessed. Results: 1,777 serology samples were tested using Roche Elecsys/-S anti-SARS-CoV-2 assays to detect total anti-N/S antibodies. 1,562 samples were tested using the POC LFA (including 50 negative controls), and 90 samples were tested using an in vitro ACE2-RBD binding inhibition surrogate neutralisation assay. The POCT demonstrated 97.7% sensitivity, 100% specificity, a positive predictive value (PPV) of 100%, and a negative predictive value (NPV) of 61% in comparison to the commercial assay. Anti-S antibody titres determined by the Roche assay stratified by the POC LFA result groups demonstrated statistically significant differences between the "Positive" and "Negative" LFA groups (p < 0.0001) and the "Weak Positive" and "Positive" LFA groups (p < 0.0001). No statistically significant difference in ACE2-RBD binding inhibition was demonstrated when stratified by the LFA POC results. A positive, statistically significant correlation was demonstrated between the in vitro pseudo-neutralisation assay results and anti-S antibody titres (rho 0.423, p < 0.001) and anti-N antibody titres (rho = 0.55, p < 0.0001). Conclusion: High sensitivity, specificity, and PPV were demonstrated for the POC LFA for the detection of anti-S-RBD antibodies in comparison to the commercial assay. The LFA was not a reliable determinant of the neutralisation capacity of identified antibodies. POC LFA are useful tools in sero-epidemiology settings, pandemic preparedness and may act as supportive tools in treatment decisions through the rapid identification of anti-Spike antibodies.

Incidence rate and predictors of COVID-19 in the two largest cities of Burkina Faso - prospective cohort study in 2021 (ANRS-COV13).

BACKGROUND: Early data on COVID-19 (based primarily on PCR testing) indicated a low burden in Sub-Saharan Africa. To better understand this, this study aimed to estimate the incidence rate and identify predictors of SARS-CoV-2 seroconversion in the two largest cities of Burkina Faso. This study is part of the EmulCOVID-19 project (ANRS-COV13). METHODS: Our study utilized the WHO Unity protocol for cohort sero-epidemiological studies of COVID-19 in general population. We conducted random sampling stratified by age group and sex. Individuals aged 10 years and older in the cities of Ouagadougou and Bobo-Dioulasso, Burkina Faso were included and surveyed at 4 time points, each 21 days apart, from March 3 to May 15, 2021. WANTAI SARS-CoV-2 Ab ELISA serological tests were used to detect total antibodies (IgM, IgG) in serum. Predictors were investigated using Cox proportional hazards regression. RESULTS: We analyzed the data from 1399 participants (1051 in Ouagadougou, 348 in Bobo-Dioulasso) who were SARS-CoV-2 seronegative at baseline and had at least one follow-up visit. The incidence rate of SARS-CoV-2 seroconversion was 14.3 cases [95%CI 13.3-15.4] per 100 person-weeks. The incidence rate was almost three times higher in Ouagadougou than in Bobo-Dioulasso (Incidence rate ratio: IRR = 2.7 [2.2-3.2], p < 0.001). The highest incidence rate was reported among women aged 19-59 years in Ouagadougou (22.8 cases [19.6-26.4] per 100 person-weeks) and the lowest among participants aged 60 years and over in Bobo-Dioulasso, 6.3 cases [4.6-8.6] per 100 person-weeks. Multivariable analysis showed that participants aged 19 years and older were almost twice as likely to seroconvert during the study period compared with those aged 10 to 18 years (Hazard ratio: HR = 1.7 [1.3-2.3], p < 0.001). Those aged 10-18 years exhibited more asymptomatic forms than those aged 19 years and older, among those who achieved seroconversion (72.9% vs. 40.4%, p < 0.001). CONCLUSION: The spread of COVID-19 is more rapid in adults and in large cities. Strategies to control this pandemic in Burkina Faso, must take this into account. Adults living in large cities should be the priority targets for vaccination efforts against COVID-19.

Estimated protection against COVID-19 based on predicted neutralisation titres from multiple antibody measurements in a longitudinal cohort, France, April 2020 to November 2021.

BackgroundThe risk of SARS-CoV-2 (re-)infection remains present given waning of vaccine-induced and infection-acquired immunity, and ongoing circulation of new variants.AimTo develop a method that predicts virus neutralisation and disease protection based on variant-specific antibody measurements to SARS-CoV-2 antigens.MethodsTo correlate antibody and neutralisation titres, we collected 304 serum samples from individuals with either vaccine-induced or infection-acquired SARS-CoV-2 immunity. Using the association between antibody and neutralisation titres, we developed a prediction model for SARS-CoV-2-specific neutralisation titres. From predicted neutralising titres, we inferred protection estimates to symptomatic and severe COVID-19 using previously described relationships between neutralisation titres and protection estimates. We estimated population immunity in a French longitudinal cohort of 905 individuals followed from April 2020 to November 2021.ResultsWe demonstrated a strong correlation between anti-SARS-CoV-2 antibodies measured using a low cost high-throughput assay and antibody response capacity to neutralise live virus. Participants with a single vaccination or immunity caused by infection were especially vulnerable to symptomatic or severe COVID-19. While the median reduced risk of COVID-19 from Delta variant infection in participants with three vaccinations was 96% (IQR: 94-98), median reduced risk among participants with infection-acquired immunity was only 42% (IQR: 22-66).ConclusionOur results are consistent with data from vaccine effectiveness studies, indicating the robustness of our approach. Our multiplex serological assay can be readily adapted to study new variants and provides a framework for development of an assay that would include protection estimates.

Sero-Epidemiology and Associated Risk Factors of Foot-and-Mouth Disease (FMD) in the Northern Border Regions of Pakistan.

The present cross-sectional survey was carried out to investigate the distribution and risk factors of FMD in Pakistan's northern border regions. About 385 serum samples were compiled from small ruminants (239) and large ruminants (146) and tested using 3ABC-Mab-bELISA. An overall apparent seroprevalence of 67.0% was documented. The highest seroprevalence of 81.1% was reported in the Swat, followed by 76.6% in Mohmand, 72.7% in Gilgit, 65.6% in Shangla, 63.4% in Bajaur, 46.6% in Chitral and lowest 46.5% in Khyber region. Statistically significant variations in seroprevalence of 51.5%, 71.8%, 58.3%, and 74.4% were recorded in sheep, goats, cattle, and buffaloes, respectively. From the different risk factors investigated, age, sex, species of animal, seasons, flock/herd size, farming methods, outbreak location, and nomadic animal movement were found to be significantly associated (p < 0.05) with the seroprevalence of FMD. It was concluded that proper epidemiological study, risk-based FMD surveillance in small ruminants, vaccination strategy, control measures for transboundary animal movement, collaborations, and awareness programs need to be practiced in the study regions to investigate the newly circulating virus strains in large and small ruminants and associated factors for the wide seroprevalence to plan proper control policies to bound the consequence of FMD in the region.

Zika, Flavivirus and Malaria Antibody Cocirculation in Nigeria.

Introduction. Arboviruses and malaria pose a growing threat to public health, affecting not only the general population but also immunocompromised individuals and pregnant women. Individuals in vulnerable groups are at a higher risk of severe complications from the co-circulation and transmission of ZIKV, malaria, and FLAVI fever. In sub-Saharan countries, such as Nigeria, these mosquito-borne infections have clinical presentations that overlap with other diseases (dengue, West Nile virus, and Japanese encephalitis, chikungunya, and O'nyong o'nyong virus), making them a diagnostic challenge for clinicians in regions where they co-circulate. Vertical transmission can have a devastating impact on maternal health and fetal outcomes, including an increased risk of fetal loss and premature birth. Despite the global recognition of the burden of malaria and arboviruses, particularly ZIKV and other flaviviruses, there is limited data on their prevalence in Nigeria. In urban settings, where these diseases are endemic and share common biological, ecological, and economic factors, they may impact treatment outcomes and lead to epidemiological synergy. Hence, it is imperative to conduct sero-epidemiological and clinical studies to better understand the disease burden and hidden endemicity, thereby enabling improved prevention and clinical management. Method. Serum samples collected from outpatients between December 2020 and November 2021 in three regions of Nigeria were tested for the presence of IgG antibody seropositivity against ZIKV and FLAVI using immunoblot serological assay. Results. The overall cohort co-circulation antibody seropositivity of ZIKV, FLAVI and malaria was 24.0% (209/871). A total of 19.2% (167/871) of the study participants had ZIKV-seropositive antibodies and 6.2% (54/871) were FLAVI-seropositive, while 40.0% (348/871) of the subjects had malaria parasite antigens. Regional analysis revealed that participants from the southern region had the highest antibody seropositivity against ZIKV (21.7% (33/152)) and FLAVI (8.6% (13/152)), whereas those from the central region had a higher malaria parasite antigen (68.5% (287/419)). Conclusions. This study represents the largest comparative cross-sectional descriptive sero-epidemiological investigation of ZIKV-FLAVI and malaria cocirculation in Nigeria. The findings of this study revealed increased antibody seropositivity, hidden endemicity, and the burden of ZIKV, FLAVI, and malaria co-circulating in Nigeria.

Sero-Epidemiological Study of Varicella in the Italian General Population.

The aim of this study was to analyze the seroprevalence of varicella in Italy and to evaluate the impact of varicella vaccination, which has been mandatory for newborns since 2017. The levels of VZV-specific IgG antibodies were determined by the ELISA method in residual serum samples obtained from subjects aged between 6 and 64 years and residing in 13 Italian regions. Overall, 3746 serum samples were collected in the years 2019 and 2020. The overall seroprevalence was 91.6% (89.9% in males and 93.3% in females; p = 0.0002). Seroprevalence showed an increasing trend (p < 0.0001) starting in the younger age groups: 6-9 years: 84.1%; 10-14 years: 88.7%; 15-19 years: 89.3%; 20-39 years: 93.1% and >40 years: 97.0%. The seroprevalence data obtained in the present study were compared with those relating to previous sero-epidemiological surveys conducted, respectively, in the years 1996-1997, 2003-2004 and 2013-2014, taking into consideration only data from regions monitored in all surveillance campaigns. The comparison highlighted for the period 2019-2020 showed significantly higher values in the age groups 6-9 (p < 0.001), 10-14 (p = 0.018) and 15-19 years (p = 0.035), while in adults, the trend did not change over time (ns). These results highlight the positive impact of varicella vaccination in Italy.

The infection rates of HBV and HCV decreased significantly in Zhejiang Province, China: A comparative study based on the data of two sero-epidemiological surveys in 1992 and 2020.

In 2020, China conducted a nationwide, sero-epidemiological, cross-sectional survey of viral hepatitis. The stratified multi-stage cluster random sampling method was used to select the permanent population aged 1-69 years, followed by questionnaire survey and sample collection and detection of the serological markers of hepatitis B (HBV) and hepatitis C viruses (HCV). A total of 4747 individuals aged 1-69 years were investigated in Zhejiang Province. The positive rates of hepatitis B surface antigen and anti-HCV were 4.3% and 0%, respectively. Compared to a similar sero-epidemiological survey in 1992, the 2020 survey showed that the HBV infection rate in Zhejiang Province decreased by 56.5%. In both surveys, HBV infection rate increased with age (in 1992, χ2  = 185.866, p = .000; in 2020, χ2  = 1383.836, p = .000). Compared with 1992, the positive anti-HCV rate in those aged 1-69 years in 2020 decreased by 100.0%. This result showed that the HBV vaccine and blood screening to prevent HBV and HCV infection significantly decreased the infection rate of HBV and HCV in the younger generation of Zhejiang province. However, the rate of HBV carriers aged 30-69 years was still high, which underscores the need to strengthen the management and treatment of chronic HBV infection. Hence, Zhejiang province can eliminate the public health threat of viral hepatitis.

Sero - epidemiology of brucellosis in people and their livestock: A linked human - animal cross-sectional study in a pastoralist community in Kenya.

Background: Brucellosis is associated with massive livestock production losses and human morbidity worldwide. Efforts to control brucellosis among pastoralist communities are limited by scarce data on the prevalence and risk factors for exposure despite the high human-animal interactions in these communities. This study simultaneously assessed the seroprevalence of brucellosis and associated factors of exposure among pastoralists and their livestock in same households. Methods: We conducted a cross-sectional study in pastoralist communities in Marsabit County - Kenya. A total of 1,074 women and 225 children participated and provided blood samples. Blood was also drawn from 1,876 goats, 322 sheep and 189 camels. Blood samples were collected to be screened for the presence of anti-Brucella IgG antibodies using indirect IgG Enzyme-Linked Immunosorbent Assay (ELISA) kits. Further, Individual, household and herd-level epidemiological information were captured using a structured questionnaire. Group differences were compared using the Pearson's Chi-square test, and p-values < 0.05 considered statistically significant. Generalized mixed-effects multivariable logistic human and animal models using administrative ward as the random effect was used to determine variables correlated to the outcome. Results: Household-level seropositivity was 12.7% (95% CI: 10.7-14.8). The individual human seroprevalence was 10.8% (9.1-12.6) with higher seroprevalence among women than children (12.4 vs. 3.1%, p < 0.001). Herd-level seroprevalence was 26.1% (23.7-28.7) and 19.2% (17.6-20.8) among individual animals. Goats had the highest seroprevalence 23.1% (21.2 - 25.1), followed by sheep 6.8% (4.3-10.2) and camels 1.1% (0.1-3.8). Goats and sheep had a higher risk of exposure OR = 3.8 (95% CI 2.4-6.7, p < 0.001) and 2.8 (1.2-5.6, p < 0.007), respectively relative to camels. Human and animal seroprevalence were significantly associated (OR = 1.8, [95%CI: 1.23-2.58], p = 0.002). Herd seroprevalence varied by household head education (OR = 2.45, [1.67-3.61, p < 0.001]) and herd size (1.01, [1.00-1.01], p < 0.001). Conclusions: The current study showed evidence that brucellosis is endemic in this pastoralist setting and there is a significant association between animal and human brucellosis seropositivity at household level representing a potential occupational risk. Public health sensitization and sustained human and animal brucellosis screening are required.

Sero-Epidemiological Study of Bordetella pertussis Infection in the Italian General Population.

A multicenter study was conducted to estimate the prevalence of pertussis IgG antibodies (anti-PTx) in the Italian population. Serum samples (4154) collected in the years 2019−2020 from subjects aged 6 to 90 years were tested. The anti-PTx IgG levels were determined by ELISA test. The limit of detection was 5 IU/mL (International Units per milliliter); values ≥ 40 IU/mL and ≥100 IU/mL indicate an infection that has occurred in recent years and a recent infection (occurred during the last year), respectively. The mean concentration of anti-PTx IgG antibodies in the tested samples was 13 IU/mL; 1.0% of subjects had a titer ≥ 100 IU/mL, 5.3% a titer between 40 and 100 IU/mL, and 38.9% a titer < 5 IU/mL. The mean antibody concentration was significantly higher in males than in females. The age group 25−39 years had the lowest percentage of negative subjects (36.9%) and the highest prevalence of subjects with antibody titers ≥ 100 IU/mL (1.3%). In the age group ≥ 65 years, the prevalence of subjects with titers between 40 and 100 IU/mL (6.7%) and the percentage of negative subjects (44.8%) was higher than in the other age groups. The results highlight the possible role of adolescents and adults in the transmission of B. pertussis.

A prospective study of risk factors associated with seroprevalence of SARS-CoV-2 antibodies in healthcare workers at a large UK teaching hospital.

OBJECTIVES: To describe the risk factors for SARS-CoV-2 infection in UK healthcare workers (HCWs). METHODS: We conducted a prospective sero-epidemiological study of HCWs at a major UK teaching hospital using a SARS-CoV-2 immunoassay. Risk factors for seropositivity were analysed using multivariate logistic regression. RESULTS: 410/5,698 (7·2%) staff tested positive for SARS-CoV-2 antibodies. Seroprevalence was higher in those working in designated COVID-19 areas compared with other areas (9·47% versus 6·16%) Healthcare assistants (aOR 2·06 [95%CI 1·14-3·71]; p=0·016) and domestic and portering staff (aOR 3·45 [95% CI 1·07-11·42]; p=0·039) had significantly higher seroprevalence than other staff groups after adjusting for age, sex, ethnicity and COVID-19 working location. Staff working in acute medicine and medical sub-specialities were also at higher risk (aOR 2·07 [95% CI 1·31-3·25]; p<0·002). Staff from Black, Asian and minority ethnic (BAME) backgrounds had an aOR of 1·65 (95% CI 1·32 - 2·07; p<0·001) compared to white staff; this increased risk was independent of COVID-19 area working. The only symptoms significantly associated with seropositivity in a multivariable model were loss of sense of taste or smell, fever, and myalgia; 31% of staff testing positive reported no prior symptoms. CONCLUSIONS: Risk of SARS-CoV-2 infection amongst HCWs is highly heterogeneous and influenced by COVID-19 working location, role, age and ethnicity. Increased risk amongst BAME staff cannot be accounted for solely by occupational factors.

Phage ImmunoPrecipitation Sequencing (PhIP-Seq): The Promise of High Throughput Serology.

Phage ImmunoPrecipitation Sequencing (PhIP-Seq) is a high throughput serological technology that is revolutionizing the manner in which we track antibody profiles. In this review, we mainly focus on its application to viral infectious diseases. Through the pull-down of patient antibodies using peptide-tile-expressing T7 bacteriophages and detection using next-generation sequencing (NGS), PhIP-Seq allows the determination of antibody repertoires against peptide targets from hundreds of proteins and pathogens. It differs from conventional serological techniques in that PhIP-Seq does not require protein expression and purification. It also allows for the testing of many samples against the whole virome. PhIP-Seq has been successfully applied in many infectious disease investigations concerning seroprevalence, risk factors, time trends, etiology of disease, vaccinology, and emerging pathogens. Despite the inherent limitations of this technology, we foresee the future expansion of PhIP-Seq in both investigative studies and tracking of current, emerging, and novel viruses. Following the review of PhIP-Seq technology, its limitations, and applications, we recommend that PhIP-Seq be integrated into national surveillance programs and be used in conjunction with molecular techniques to support both One Health and pandemic preparedness efforts.