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1.
PLoS One ; 16(4): e0248813, 2021.
Article in English | MEDLINE | ID: mdl-33831032

ABSTRACT

Healthcare personnel are at risk to aquire the corona virus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We evaluated the prevalence of SARS-CoV-2 antibodies and positive nasopharyngeal reverse transcriptase polymerase-chain reaction (RT-PCR) tests in German intensive care and emergency physicians. Physicians attending intensive care and emergency medicine training courses between June 16th and July 2nd 2020 answered a questionnaire and were screened for SARS-CoV-2 antibodies via automated electrochemiluminiscence immunoassay. We recruited 516 physicans from all parts of Germany, 445/516 (86%) worked in high risk areas, and 379/516 (73%) had treated patients with COVID-19. The overall positive rate was 18/516 (3.5%), 16/18 (89%) had antibodies against SARS-COV-2, another 2 reported previous positive RT-PCR results although antibody testing was negative. Of those positive, 7/18 (39%) were unaware of their infection. A stay abroad was stated by 173/498 (35%), mostly in Europe. 87/516 (17%) reported a febrile respiratory infection after January 1st 2020 which was related to SARS-CoV-2 in 4/87 (4.6%). Contact to COVID-19 positive relatives at home was stated by 22/502 (4.4%). This was the only significant risk factor for Covid-19 infection (Fisher´s exact test, p = 0.0005). N95 masks and eye protection devices were available for 87% and 73%, respectively. A total of 254/502 (51%) had been vaccinated against seasonal influenza. The overall SARS-CoV-2 infection rate of german physicians from intensive care and emergency medicine was low compared to reports from other countries and settings. This finding may be explained by the fact that the German health care system was not overwhelmed by the first wave of the SARS-CoV-2 pandemic.


Subject(s)
Antibodies, Viral/blood , Critical Care , Physicians , /metabolism , Adult , Aged , /diagnosis , Female , Germany/epidemiology , Humans , Male , Middle Aged , Prevalence , Seroepidemiologic Studies
3.
BMJ Open ; 11(4): e045425, 2021 04 01.
Article in English | MEDLINE | ID: mdl-33795310

ABSTRACT

OBJECTIVES: We aimed to review SARS-CoV-2 seroprevalence studies conducted in Europe to understand how they may be used to inform ongoing control strategies for COVID-19. DESIGN: Scoping review of peer-reviewed publications and manuscripts on preprint servers from January 2020 to 15 September 2020. PRIMARY MEASURE: Seroprevalence estimate (and lower and upper CIs). For studies conducted across a country or territory, we used the seroprevalence estimate and the upper and lower CIs and compared them to the total number of reported infections to calculate the ratio of reported to expected infections. RESULTS: We identified 23 population-based seroprevalence studies conducted in Europe. Among 12 general population studies, seroprevalence ranged from 0.42% among residual clinical samples in Greece to 13.6% in an area of high transmission in Gangelt, Germany. Of the eight studies in blood donors, seroprevalence ranged from 0.91% in North-Western Germany to 23.3% in a high-transmission area in Lombardy region, Italy. In three studies which recruited individuals through employment, seroprevalence ranged from 0.5% among factory workers in Frankfurt, Germany, to 10.2% among university employees in Milan, Italy. In comparison to nationally reported cases, the extent of infection, as derived from these seroprevalence estimates, is manyfold higher and largely heterogeneous. CONCLUSION: Exposure to the virus in Europe has not reached a level of infection that would prevent further circulation of the virus. Effective vaccine candidates are urgently required to deliver the level of immunity in the population.


Subject(s)
Antibodies, Viral/blood , Seroepidemiologic Studies , /blood , Europe/epidemiology , Germany , Greece , Humans , Italy , Pandemics
4.
Article in English | MEDLINE | ID: mdl-33804893

ABSTRACT

BACKGROUND: Healthcare workers (HCWs) have been the key players in the fight against the coronavirus disease 2019 (COVID-19) pandemic. The aim of our study was to evaluate the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG anti-bodies. METHODS: We conducted a cross-sectional study among workers of two hospitals and Territorial Medical and Administrative services in Northern Italy. From 8 May to 3 June 2020, 2252 subjects were tested. Seroprevalence and 95% confidence interval (CI) were calculated for all individuals who were stratified by job title, COVID-19 risk of exposure, direct contact with patients, unit ward, and intensity of care. RESULTS: Median age was 50 years, and 72% of subjects were female. The overall seroprevalence was 17.11% [95% CI 15.55-18.67]. Around 20% of healthcare assistants were seropositive, followed by physicians and nurses (16.89% and 15.84%, respectively). HCWs with high risk of exposure to COVID-19 were more frequently seropositive (28.52%) with respect to those with medium and low risks (16.71% and 12.76%, respectively). Moreover, personnel in direct contact had higher prevalence (18.32%) compared to those who did not (10.66%). Furthermore, the IgG were more frequently detected among personnel of one hospital (19.43%). CONCLUSION: The high seroprevalence observed can be partially explained by the timing and the population seroprevalence; the study was conducted in an area with huge spread of the infection.


Subject(s)
Antibodies, Viral , Cross-Sectional Studies , Female , Health Personnel , Hospitals , Humans , Italy/epidemiology , Middle Aged , Seroepidemiologic Studies
5.
Article in English | MEDLINE | ID: mdl-33805139

ABSTRACT

Coronavirus disease 2019 (COVID-19) is an acute infectious disease caused by the novel coronavirus (SARS-CoV-2) identified in 2019. The COVID-19 outbreak continues to have devastating consequences for human lives and the global economy. The B-LiFe mobile laboratory in Piedmont, Italy, was deployed for the surveillance of COVID-19 cases by large-scale testing of first responders. The objective was to assess the seroconversion among the regional civil protection (CP), police, health care professionals, and volunteers. The secondary objective was to detect asymptomatic individuals within this cohort in the light of age, sex, and residence. In this paper, we report the results of serological testing performed by the B-LiFe mobile laboratory deployed from 10 June to 23 July 2020. The tests included whole blood finger-prick and serum sampling for detection of SARS-CoV-2 spike receptor-binding domain (S-RBD) antibodies. The prevalence of SARS-CoV-2 antibodies was approximately 5% (294/6013). The results of the finger-prick tests and serum sample analyses showed moderate agreement (kappa = 0.77). Furthermore, the detection rates of serum antibodies to the SARS-CoV-2 nucleocapsid protein (NP) and S-RBD among the seroconverted individuals were positively correlated (kappa = 0.60), at least at the IgG level. Seroprevalence studies based on serological testing for the S-RBD protein or SARS-CoV-2 NP antibodies are not sufficient for diagnosis but might help in screening the population to be vaccinated and in determining the duration of seroconversion.


Subject(s)
Laboratories , Antibodies, Viral , Humans , Immunoglobulin G , Immunoglobulin M , Italy/epidemiology , Seroepidemiologic Studies
6.
J Zoo Wildl Med ; 52(1): 14-27, 2021 Apr.
Article in English | MEDLINE | ID: mdl-33827157

ABSTRACT

Feline coronavirus (FCoV) is reported worldwide and known to cause disease in domestic and nondomestic felid species. Although FCoV often results in mild to inapparent disease, a small subset of cats succumb to the fatal, systemic disease feline infectious peritonitis (FIP). An outbreak of FIP in Cheetahs (Acinonyx jubatus) in a zoological collection demonstrated the devastating effect of FCoV introduction into a naïve group of animals. In addition to cheetahs, FIP has been described in European wildcats (Felis silvestris), a tiger (Panthera tigris), a mountain lion (Puma concolor), and lion (Panthera leo). This paper reviews the reported cases of FIP in nondomestic felid species and highlights the surveys of FCoV in populations of nondomestic felids.


Subject(s)
Coronavirus, Feline/pathogenicity , Felidae/virology , Feline Infectious Peritonitis/virology , Africa/epidemiology , Animals , Animals, Wild , Animals, Zoo , Brazil/epidemiology , Cats , Europe/epidemiology , Feline Infectious Peritonitis/epidemiology , Feline Infectious Peritonitis/mortality , Female , Male , North America/epidemiology , Seroepidemiologic Studies
7.
Front Public Health ; 9: 636023, 2021.
Article in English | MEDLINE | ID: mdl-33796497

ABSTRACT

This work presents simulation results for different mitigation and confinement scenarios for the propagation of COVID-19 in the metropolitan area of Madrid. These scenarios were implemented and tested using EpiGraph, an epidemic simulator which has been extended to simulate COVID-19 propagation. EpiGraph implements a social interaction model, which realistically captures a large number of characteristics of individuals and groups, as well as their individual interconnections, which are extracted from connection patterns in social networks. Besides the epidemiological and social interaction components, it also models people's short and long-distance movements as part of a transportation model. These features, together with the capacity to simulate scenarios with millions of individuals and apply different contention and mitigation measures, gives EpiGraph the potential to reproduce the COVID-19 evolution and study medium-term effects of the virus when applying mitigation methods. EpiGraph, obtains closely aligned infected and death curves related to the first wave in the Madrid metropolitan area, achieving similar seroprevalence values. We also show that selective lockdown for people over 60 would reduce the number of deaths. In addition, evaluate the effect of the use of face masks after the first wave, which shows that the percentage of people that comply with mask use is a crucial factor for mitigating the infection's spread.


Subject(s)
/transmission , Computer Simulation , Social Networking , Algorithms , /prevention & control , Cities , Communicable Disease Control , Epidemics , Humans , Masks , Quarantine , Seroepidemiologic Studies , Spain , Travel
8.
Curr Oncol ; 28(2): 1249-1255, 2021 03 16.
Article in English | MEDLINE | ID: mdl-33809772

ABSTRACT

The new Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) coronavirus has generated a pandemic, in which there are population groups at higher risk and who are potentially fatal victims of the disease. Cancer patients have been considered a group with special susceptibility, particularly patients with lung tumour involvement and haematological neoplasms. The Spanish Lymphoma Oncology Group (GOTEL) carried out a multicenter study of SARS-CoV-2 seroprevalence in patients with lymphoma. Results: A total of 150 patients were included between 22 May and 11 June 2020. The mean age was 65 years (range 17-89), 70 women (46.5%) and 80 men (53, 5%). At the time of diagnosis of lymphoma, 13 cases were stage I (9%), 27 (18%) stage II, 37 (24.5%) stage III, and 73 (48.5%) stage IV, while 6.6% had a primary extranodal origin. A total of 10 cases with positive serology for SARS-CoV-2 were identified, which is a prevalence of 6% in this population. None of the patients required intensive care unit management and all fully recovered from the infection. Conclusion: IgG antibody seroprevalence in lymphoma patients appears similar to that of the general population and does not show greater aggressiveness.


Subject(s)
Antibodies, Viral/blood , Lymphoma/virology , Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Immunoglobulin G/blood , Lymphoma/blood , Lymphoma/drug therapy , Lymphoma/pathology , Male , Middle Aged , Seroepidemiologic Studies , Spain/epidemiology , Young Adult
9.
Trop Biomed ; 38(1): 28-32, 2021 Mar 01.
Article in English | MEDLINE | ID: mdl-33797520

ABSTRACT

Infectious bronchitis viral (IBV) (Avian coronavirus) diseases is among the major reproductive diseases affecting the avian production in Africa. There is scanty information on its current status and vaccination compliance among captive wild birds (CWB) and indigenous chickens (LC) in Nigeria. This study aimed to assess the exposure and the risk factors associated with IBV in CWB and LC from North-central and South west regions of Nigeria. Sera samples from 218 LC and 43 CWB were examined for IBV IgG using enzyme linked immunosorbent assay. Also, owners of LC and managers of CWB were interviewed using a pre-tested structured checklist. An overall IBV prevalence of 42.9% (112/261) was obtained. Captive wild birds and indigenous chickens had 11.6% (5/43) and 49.1% (107/218) prevalence respectively with a significant difference (p< 0.0001, OR= 7.3, 95% CI= 2.8-19.3). Also, geo-location indicated significant difference in IBV exposure among birds (p<=0.034). Furthermore, the study showed that there had never been laboratory screening on all acquired wild birds for exposure to infectious agents in the study location while none of these birds (LB/CWB) had history of vaccination. Since IBV is endemic in Nigeria, the use of vaccine for prophylactic measure should be advocated among LC and CWB owners in order to avoid unnecessary losses. Also, the essence of screening for infectious agents in newly acquired wild birds should be considered crucial for health sustenance and public safety.


Subject(s)
Animals, Wild/virology , Chickens/virology , Coronavirus Infections/veterinary , Infectious bronchitis virus , Animals , Animals, Wild/immunology , Chickens/immunology , Coronavirus Infections/epidemiology , Enzyme-Linked Immunosorbent Assay/veterinary , Nigeria/epidemiology , Seroepidemiologic Studies
10.
Article in English | MEDLINE | ID: mdl-33800721

ABSTRACT

Healthcare workers are at the forefront against COVID-19, worldwide. Since Fondazione Policlinico Universitario A. Gemelli (FPG) IRCCS was enlisted as a COVID-19 hospital, the healthcare workers deployed to COVID-19 wards were separated from those with limited/no exposure, whereas the administrative staff were designated to work from home. Between 4 June and 3 July 2020, an investigation was conducted to evaluate the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglobulin (IgG) antibodies among the employees of the FPG using point-of-care (POC) and venous blood tests. Sensitivity, specificity, and predictive values were determined with reverse-transcription polymerase chain reaction on nasal/oropharyngeal swabs as the diagnostic gold standard. The participants enrolled amounted to 4777. Seroprevalence was 3.66% using the POC test and 1.19% using the venous blood test, with a significant difference (p < 0.05). The POC test sensitivity and specificity were, respectively, 63.64% (95% confidence interval (CI): 62.20% to 65.04%) and 96.64% (95% CI: 96.05% to 97.13%), while those of the venous blood test were, respectively, 78.79% (95% CI: 77.58% to 79.94%) and 99.36% (95% CI: 99.07% to 99.55%). Among the low-risk populations, the POC test's predictive values were 58.33% (positive) and 98.23% (negative), whereas those of the venous blood test were 92.86% (positive) and 98.53% (negative). According to our study, these serological tests cannot be a valid alternative to diagnose COVID-19 infection in progress.


Subject(s)
Antibodies, Viral , Health Personnel , Hospitals , Humans , Rome , Seroepidemiologic Studies , Serologic Tests
11.
Article in English | MEDLINE | ID: mdl-33806642

ABSTRACT

After the first pandemic wave, a nationwide survey assessed the seroprevalence of SARS-CoV-2 antibodies in Spain and found notable differences among provinces whose causes remained unclear. This ecological study aimed to analyze the association between environmental and demographic factors and SARS-CoV-2 infection by province. The seroprevalence of SARS-CoV-2 antibodies by province was obtained from a nationwide representative survey performed in June 2020, after the first pandemic wave in Spain. Linear regression was used in the analysis. The seroprevalence of SARS-CoV-2 antibodies of the 50 provinces ranged from 0.2% to 13.6%. The altitude, which ranged from 5 to 1131 m, explained nearly half of differences in seroprevalence (R2 = 0.47, p < 0.001). The seroprevalence in people residing in provinces above the median altitude (215 m) was three-fold higher (6.5% vs. 2.1%, p < 0.001). In the multivariate linear regression, the addition of population density significantly improved the predictive value of the altitude (R2 = 0.55, p < 0.001). Every 100 m of altitude increase and 100 inhabitants/km2 of increase in population density, the seroprevalence rose 0.84 and 0.63 percentage points, respectively. Environmental conditions related to higher altitude in winter-spring, such as lower temperatures and absolute humidity, may be relevant to SARS-CoV-2 transmission. Places with such adverse conditions may require additional efforts for pandemic control.


Subject(s)
Altitude , Antibodies, Viral , Humans , Immunoglobulin G , Pandemics , Seroepidemiologic Studies , Spain/epidemiology
12.
Article in English | MEDLINE | ID: mdl-33808716

ABSTRACT

Lack of knowledge around seroprevalence levels of COVID-19 in Poland was the reason for the implementation of a seroepidemiological study in the Katowice Region (2,100,000 inhabitants). In October-November 2020, a questionnaire examination and measurement of anti-SARS-CoV-2 IgG and IgM antibodies were performed in a random sample of the general population (n = 1167). The objectives of the study were to estimate the prevalence of IgG and IgM antibodies and to assess their host-related correlates. The prevalence of IgG seropositivity was 11.4% (95% CI: 9.5-13.2%) and IgM seropositivity was 4.6% (95% CI: 3.5-5.8%). Diagnosis of COVID-19 was found in 4.8% of subjects. A positive IgG test was statistically significantly associated with age (inverse relationship), a person's contact with a COVID-19 patient, quarantine, and two symptoms in the past: fever and loss of smell/taste. Positive IgG tests were less prevalent in subjects who had diagnoses of arterial hypertension, diabetes, or rheumatologic disorders. IgM test positivity was associated with quarantine and loss of smell/taste only with no effect of chronic diseases found. In Poland, in the period October-November 2020, the prevalence of SARS-CoV-2 infection was larger than earlier estimates obtained in other European countries, probably reflecting the measurements obtained during the "second wave" of the epidemic.


Subject(s)
Antibodies, Viral , Europe , Humans , Immunoglobulin M , Poland/epidemiology , Seroepidemiologic Studies
14.
PLoS One ; 16(4): e0238088, 2021.
Article in English | MEDLINE | ID: mdl-33793556

ABSTRACT

BACKGROUND: COVID-19 seroprevalence data, particularly in less developed countries with a relatively low incidence, has been scant. We aimed to explore the seroprevalence of hospital staff in the area with zero confirmed COVID-19 case to shed light on the situation of COVID-19 infection in zero or low infection rate countries where mass screening was not readily available. METHODS: A locally developed rapid immunoglobulin M (IgM)/immunoglobulin G (IgG) test kit was used for hospital staff screening of Ranong hospital which is located in a province with zero COVID-19 prevalence in Thailand from 17th April to 17th May 2020. All staff was tested, 100 of which were randomly invited to have a repeating antibody test in one month. (Thai Clinical Trials Registry: TCTR20200426002). RESULTS: Of 844 hospital staff, 82 were tested twice one month apart (response rate for repeating antibody test 82%). Overall, 0.8% of the participants (7 of 844) had positive IgM, none had positive IgG. Female staff had 1.0% positive IgM (95% CI: 0.5-2.1%) while male had 0.5% positive IgM (95% CI: 0.1-2.6%). No participants with a history of travel to the high-risk area or close contact with PCR-confirmed COVID-19 case developed SARS-CoV-2 antibodies. Among 844 staff, 811 had no symptoms and six of them developed IgM seropositive (0.7%) while 33 had minor symptoms and only one of them developed IgM seropositive (3.0%). No association between SARS-CoV-2 IgM status and gender, history of travel to a high-risk area, close contact with PCR-confirmed or suspected COVID-19 case, presence of symptoms within 14 days, or previous PCR status was found. None of the hospital staff developed SARS-CoV-2 IgG. CONCLUSIONS: COVID-19 antibody test could detect a considerable number of hospital staff who could be potential silent spreaders in a province with zero COVID-19 cases. Accurate antibody testing is a valuable screening tool, particularly in asymptomatic healthcare workers. Trial registration: This study was approved by the Institutional Review Board of Chulalongkorn University (IRB No.236/63) and the Institutional Review Board of Ranong Hospital. (Thai Clinical Trials Registry: TCTR20200426002).


Subject(s)
Antibodies, Viral/blood , Immunoglobulin G/blood , Immunoglobulin M/blood , Personnel, Hospital/statistics & numerical data , Adult , Female , Humans , Male , Middle Aged , Seroepidemiologic Studies , Thailand/epidemiology
15.
PLoS One ; 16(4): e0249550, 2021.
Article in English | MEDLINE | ID: mdl-33793673

ABSTRACT

Data on the prevalence of the SARS-CoV-2 antibody in healthcare workers (HCWs) is scarce, especially in pediatric settings. The purpose of this study was to evaluate SARS-CoV-2 IgG-positivity among HCWs of a tertiary pediatric hospital. In addition, follow-up of the serological response in the subgroup of seropositive HCWs was analysed, to gain some insight on the persistence of IgG antibodies to SARS-CoV-2. We performed a retrospective analysis of voluntary SARS-CoV-2 IgG testing, which was made available free of charge to HCWs of the Children's Memorial Health Institute in Warsaw (Poland). Plasma samples were collected between July 1 and August 9, 2020, and tested using the Abbott SARS-CoV-2 IgG assay. Of 2,282 eligible participants, 1,879 (82.3%) HCWs volunteered to undergo testing. Sixteen HCWs tested positive for SARS-CoV-2 IgG, corresponding to a seroprevalence of 0.85%. Among seropositive HCWs, three HCWs had confirmed COVID-19. Nine (56.3%) of the seropositive HCWs reported neither symptoms nor unprotected contact with confirmed SARS-CoV-2 cases in the previous months. A decline in the IgG index was observed at a median time of 86.5 days (range:84‒128 days) after symptom onset or RT-PCR testing. Further studies are necessary to elucidate the duration of persistence of anti-SARS-CoV-2 antibodies, as well as the correlation between seropositivity and protective immunity against reinfection. Regardless of the persistence of antibodies and their protective properties, such low prevalence indicates that this population is vulnerable to a second wave of the COVID-19 pandemic.


Subject(s)
Antibodies, Viral/blood , Health Personnel/statistics & numerical data , Immunoglobulin G/blood , /immunology , Adult , /immunology , Female , Hospitals, Pediatric/statistics & numerical data , Humans , Male , Middle Aged , Pandemics , Poland , Prevalence , Retrospective Studies , Seroepidemiologic Studies , Tertiary Care Centers/statistics & numerical data
16.
PLoS One ; 16(4): e0248946, 2021.
Article in English | MEDLINE | ID: mdl-33798211

ABSTRACT

BACKGROUND: Accurate seroprevalence estimates of SARS-CoV-2 in different populations could clarify the extent to which current testing strategies are identifying all active infection, and hence the true magnitude and spread of the infection. Our primary objective was to identify valid seroprevalence studies of SARS-CoV-2 infection and compare their estimates with the reported, and imputed, COVID-19 case rates within the same population at the same time point. METHODS: We searched PubMed, Embase, the Cochrane COVID-19 trials, and Europe-PMC for published studies and pre-prints that reported anti-SARS-CoV-2 IgG, IgM and/or IgA antibodies for serosurveys of the general community from 1 Jan to 12 Aug 2020. RESULTS: Of the 2199 studies identified, 170 were assessed for full text and 17 studies representing 15 regions and 118,297 subjects were includable. The seroprevalence proportions in 8 studies ranged between 1%-10%, with 5 studies under 1%, and 4 over 10%-from the notably hard-hit regions of Gangelt, Germany; Northwest Iran; Buenos Aires, Argentina; and Stockholm, Sweden. For seropositive cases who were not previously identified as COVID-19 cases, the majority had prior COVID-like symptoms. The estimated seroprevalences ranged from 0.56-717 times greater than the number of reported cumulative cases-half of the studies reported greater than 10 times more SARS-CoV-2 infections than the cumulative number of cases. CONCLUSIONS: The findings show SARS-CoV-2 seroprevalence is well below "herd immunity" in all countries studied. The estimated number of infections, however, were much greater than the number of reported cases and deaths in almost all locations. The majority of seropositive people reported prior COVID-like symptoms, suggesting that undertesting of symptomatic people may be causing a substantial under-ascertainment of SARS-CoV-2 infections.


Subject(s)
Antibodies, Viral/blood , Immunoglobulin Isotypes/blood , Adolescent , Adult , Aged , Argentina , /immunology , Female , Germany , Humans , Immunity, Herd , Incidence , Iran , Male , Middle Aged , Seroepidemiologic Studies , Sweden , Young Adult
17.
Sci Prog ; 104(2): 368504211009673, 2021.
Article in English | MEDLINE | ID: mdl-33884941

ABSTRACT

On January 30, 2020, the World Health Organization (WHO) declared SARS-CoV-2 a global pandemic, based on a high infection rate and a high case fatality rate (CFR). The combination of these two points led WHO to forecast a high expected mortality rate of approximately 2% of the population. The phenomenon of Simpson's paradox teaches us that we should be careful when we combine two variables together. Indeed, despite the high mortality rate in several places, this forecast seems to have collapsed. We believe one of the reasons for the erroneous forecasts is that combining the above points ignored a confounding variable - many of the virus carriers are asymptomatic and therefore not diagnosed.


Subject(s)
Adult , Humans , Los Angeles , Pandemics , Seroepidemiologic Studies
18.
Article in English | MEDLINE | ID: mdl-33922895

ABSTRACT

SARS-CoV-2 is a worldwide challenge for the medical sector. Healthcare workers (HCW) are a cohort vulnerable to SARS-CoV-2 infection due to frequent and close contact with COVID-19 patients. However, they are also well trained and equipped with protective gear. The SARS-CoV-2 IgG antibody status was assessed at three different time points in 450 HCW of the University Hospital Essen in Germany. HCW were stratified according to contact frequencies with COVID-19 patients in (I) a high-risk group with daily contacts with known COVID-19 patients (n = 338), (II) an intermediate-risk group with daily contacts with non-COVID-19 patients (n = 78), and (III) a low-risk group without patient contacts (n = 34). The overall seroprevalence increased from 2.2% in March-May to 4.0% in June-July to 5.1% in October-December. The SARS-CoV-2 IgG detection rate was not significantly different between the high-risk group (1.8%; 3.8%; 5.5%), the intermediate-risk group (5.1%; 6.3%; 6.1%), and the low-risk group (0%, 0%, 0%). The overall SARS-CoV-2 seroprevalence remained low in HCW in western Germany one year after the outbreak of COVID-19 in Germany, and hygiene standards seemed to be effective in preventing patient-to-staff virus transmission.


Subject(s)
Follow-Up Studies , Germany/epidemiology , Health Personnel , Humans , Seroepidemiologic Studies
19.
Article in English | MEDLINE | ID: mdl-33925518

ABSTRACT

SARS-CoV-2 continues to widely circulate in populations globally. Underdetection is acknowledged and is problematic when attempting to capture the true prevalence. Seroprevalence studies, where blood samples from a population sample are tested for SARS-CoV-2 antibodies that react to the SARS-CoV-2 virus, are a common method for estimating the proportion of people previously infected with the virus in a given population. However, obtaining reliable estimates from seroprevalence studies is challenging for a number of reasons, and the uncertainty in the results is often overlooked by scientists, policy makers, and the media. This paper reviews the methodological issues that arise in designing these studies, and the main sources of uncertainty that affect the results. We discuss the choice of study population, recruitment of subjects, uncertainty surrounding the accuracy of antibody tests, and the relationship between antibodies and infection over time. Understanding these issues can help the reader to interpret and critically evaluate the results of seroprevalence studies.


Subject(s)
Antibodies, Viral , Humans , Prevalence , Seroepidemiologic Studies , Uncertainty
20.
Article in English | MEDLINE | ID: mdl-33925680

ABSTRACT

A door-to-door survey was organised in Cuenca, Ecuador, to determine the prevalence of COVID-19 infection and adherence of the population to COVID-19 preventive measures. A total of 2457 persons participated in the study; 584 (23.7%) reported having experienced at least one flu-like symptom since the onset of the pandemic. The maximum SARS-CoV-2 seroprevalence in Cuenca was 13.2% (CI: 12-14.6%) (IgM or IgG positive). Considering PCR confirmed infections, the prevalence was 11% (CI: 10-12.4%). There was no significant difference in seroprevalence between rural and urban areas. Participants aged 35-49 years old, living with a COVID-19 positive person, at least six people in a household, physical contact with someone outside the household, a contact with a person outside the home with flu-like symptoms, using public transport, and not having enough resources for living, significantly increased the odds for SARS-CoV-2 seropositivity. Overall, there was good adherence to COVID-19 preventive measures. Having known someone who tested positive for COVID-19, having a primary or secondary level of education, and having enough resources for living, significantly increased the odds for higher adherence. In conclusion, despite good overall adherence of the population of Cuenca with COVID-19 preventive measures, our study suggests high ongoing COVID-19 transmission in Cuenca, particularly in certain parishes. Prevention should not only focus on behavioural change, but on intensified testing strategies in demographical risk groups.


Subject(s)
Adult , Cross-Sectional Studies , Ecuador/epidemiology , Humans , Middle Aged , Seroepidemiologic Studies
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