Level of Fear and Its Determinants in the Indian Population Due to COVID-19 Disease.

Background The novel coronavirus disease 2019 (COVID-19) infection was declared a global health emergency by the World Health Organization. A total of three waves across most of the states in India have been reported to date, during which strict lockdown was imposed and conditional relaxations were offered between the subsequent waves. Amid the high morbidity and mortality, there has been severe psychological distress among people which has led to mental health impairment. Methodology We investigated the level of fear in the Indian population due to COVID-19 using the Fear of COVID-19 Scale (FCS-19) and various factors influencing it. A cross-sectional study was undertaken across India among participants more than 18 years of age by recruiting participants through social media platforms such as WhatsApp and Instagram. Along with the FCS-19 questionnaire, sociodemographic information about the participants, preexisting history of comorbidities, and psychiatric illnesses were collected. The study sample was drawn by convenience technique, and the data were collected over two months from October 2021 to December 2021. Results A total of 419 participants (212 females and 207 males) participated in the study. The mean FCS-19 score of the population was 18.29 ± 6.43 (SD). Participants with a history of COVID-19-related deaths in their own family or surrounding areas had a significantly higher FCS-19 score than those without a history of COVID-19-related deaths. The mean FCS-19 score for healthcare professionals was also significantly lower than for other professions. FCS-19 scores were significantly higher among participants with psychiatric conditions than those without. Conclusions The study showed a positive association between a preexisting mental health disease and FCS-19 score and a negative association if the participant was a healthcare professional. While other factors such as age, gender, residential area, and preexisting comorbidity did not show a significant association with fear associated with COVID-19.

COVID-19 Vaccine Acceptance and Its Determinants in the General Population of Delhi, India: A State Level Cross-Sectional Survey.

OBJECTIVE: To ascertain the COVID-19 vaccination acceptance and the factors contributing to vaccine hesitancy and vaccine confidence in the adult population, and the intention for vaccination of their children. METHODS: This cross-sectional analysis reports the ancillary results of a population-based SARS-CoV-2 serosurvey conducted in Delhi, India, from September 24 to October 14, 2021. Data were collected from 20312 adult participants through a multistage sampling method from all the 274 wards in the 11 districts of the national capital territory region. RESULTS:  We enrolled 12093 (59.3%) females and 8219 (40.5%) male participants with mean (SD) age of 40.3 (14.6) years. The vaccine acceptance rate in the participants was 67.7% (95% CI 67.1, 68.4), with 6031 (43.8%) having received one dose and 7727 (56.2%) having received two vaccine doses. On adjusted analysis, lack of vaccine acceptance was independently associated with female gender aOR 1.15 (95% CI 1.1, 1.23), younger age-group (18-49 years) aOR 1.85 (95% CI 1.71, 2.0), low educational status aOR 1.88 (95% CI 1.77, 2.0), in those with no history of COVID-19 aOR 1.81 (95% CI 1.69, 1.95), non-healthcare workers aOR 2.1 (95% CI 1.7, 2.53), and in the absence of hypertension comorbidity aOR 1.22 (1.1, 1.38). Lack of awareness of COVID-19 vaccines, including doubts on vaccine efficacy and long-term safety, were primary drivers of vaccine hesitancy in the unvaccinated subgroup. Only 35.6% participants reported a positive intention to vaccinate their children. CONCLUSIONS: One in three adults lacked vaccine acceptance. High prevalence of delay in second dose vaccination was also observed.

Level of Fear and Its Determinants in the Indian Population Due to COVID-19 Disease

Background The novel coronavirus disease 2019 (COVID-19) infection was declared a global health emergency by the World Health Organization. A total of three waves across most of the states in India have been reported to date, during which strict lockdown was imposed and conditional relaxations were offered between the subsequent waves. Amid the high morbidity and mortality, there has been severe psychological distress among people which has led to mental health impairment. Methodology We investigated the level of fear in the Indian population due to COVID-19 using the Fear of COVID-19 Scale (FCS-19) and various factors influencing it. A cross-sectional study was undertaken across India among participants more than 18 years of age by recruiting participants through social media platforms such as WhatsApp and Instagram. Along with the FCS-19 questionnaire, sociodemographic information about the participants, preexisting history of comorbidities, and psychiatric illnesses were collected. The study sample was drawn by convenience technique, and the data were collected over two months from October 2021 to December 2021. Results A total of 419 participants (212 females and 207 males) participated in the study. The mean FCS-19 score of the population was 18.29 ± 6.43 (SD). Participants with a history of COVID-19-related deaths in their own family or surrounding areas had a significantly higher FCS-19 score than those without a history of COVID-19-related deaths. The mean FCS-19 score for healthcare professionals was also significantly lower than for other professions. FCS-19 scores were significantly higher among participants with psychiatric conditions than those without. Conclusions The study showed a positive association between a preexisting mental health disease and FCS-19 score and a negative association if the participant was a healthcare professional. While other factors such as age, gender, residential area, and preexisting comorbidity did not show a significant association with fear associated with COVID-19.

Neutralizing antibody responses to SARS-CoV-2: A population based seroepidemiological analysis.

This study (August-September 2021) estimated the seroprevalence of SARS-CoV-2 neutralizing antibodies in the general population of Delhi and correlated it with their anti-SARS-CoV-2 IgG levels. Samples were selected by simple random sampling method. The neutralizing capacity was estimated by performing a surrogate virus neutralization test (sVNT) (GenScript), Piscataway, NJ, USA. A total of 2233 (87.1%, 95% C.I. 85.7, 88.3) of the 2564 SARS-CoV-2 IgG seropositive samples had detectable SARS-CoV-2 neutralizing antibodies. In samples with S/CO â€‹≥ â€‹4.00, the neutralizing antibodies ranged from 94.5% to 100%. The SARS-CoV-2 neutralizing antibody seroprevalence strongly correlated with the S/CO range of IgG SARS-CoV-2 (r â€‹= â€‹0.62, p â€‹= â€‹0.002).

SARS-CoV-2 Seroprevalence in Delhi, India, During September-October 2021: A Population-Based Seroepidemiological Study.

Background A previous community-based severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serosurvey in Delhi in January 2021 reported a seroprevalence of 50.52%. We conducted a repeat serosurvey to obtain a recent estimate of the seroprevalence of IgG SARS-CoV-2 in the general population of Delhi, India. Methods This cross-sectional study was conducted from September 24 to October 14, 2021, in 274 wards of Delhi among 27,811 participants through a multistage sampling technique. Results The crude seroprevalence was 89.5% (95% CI 89.1, 89.8), weight for age and sex was 88% (95% CI 87.6, 88.4), and after adjustment for assay performance was estimated as 97.5% (95% CI 97.0, 98.0). On adjusted analysis, the odds of seroconversion in the participants vaccinated with at least one dose of either COVID-19 vaccine (Covishield/Covaxin) was more than four times compared to the unvaccinated ones (aOR 4.2 (3.8, 4.6)). 86.8% of the seropositive individuals had a SARS-CoV-2 signal/cut-off ≥4.0 although it was significantly lower in the pediatric age group. Post-second wave (August to October 2021), on average there were daily 39 new COVID-19 cases and 0.44 deaths which during Omicron driven the third wave in January to March 2022 increased to daily 4,267 cases and 11.6 deaths. Conclusion A high prevalence of IgG antibodies against SARS-CoV-2 with likely higher antibody titres in the vaccinated compared to the unvaccinated groups with evidence of hybrid immunity in a majority of the population was protective against severe disease during transmission of subsequent omicron variants.

COVID-19 Vaccine Acceptance and Its Determinants in the General Population of Delhi, India: A State Level Cross-Sectional Survey

Objective: To ascertain the COVID-19 vaccination acceptance and the factors contributing to vaccine hesitancy and vaccine confidence in the adult population, and the intention for vaccination of their children. Methods: This cross-sectional analysis reports the ancillary results of a population-based SARS-CoV-2 serosurvey conducted in Delhi, India, from September 24 to October 14, 2021. Data were collected from 20312 adult participants through a multistage sampling method from all the 274 wards in the 11 districts of the national capital territory region. Results: We enrolled 12093 (59.3%) females and 8219 (40.5%) male participants with mean (SD) age of 40.3 (14.6) years. The vaccine acceptance rate in the participants was 67.7% (95% CI 67.1, 68.4), with 6031 (43.8%) having received one dose and 7727 (56.2%) having received two vaccine doses. On adjusted analysis, lack of vaccine acceptance was independently associated with female gender aOR 1.15 (95% CI 1.1, 1.23), younger age-group (18-49 years) aOR 1.85 (95% CI 1.71, 2.0), low educational status aOR 1.88 (95% CI 1.77, 2.0), in those with no history of COVID-19 aOR 1.81 (95% CI 1.69, 1.95), non-healthcare workers aOR 2.1 (95% CI 1.7, 2.53), and in the absence of hypertension comorbidity aOR 1.22 (1.1, 1.38). Lack of awareness of COVID-19 vaccines, including doubts on vaccine efficacy and long-term safety, were primary drivers of vaccine hesitancy in the unvaccinated subgroup. Only 35.6% participants reported a positive intention to vaccinate their children. Conclusions: One in three adults lacked vaccine acceptance. High prevalence of delay in second dose vaccination was also observed.

Seroprevalence of immunoglobulin G antibodies against SARS-CoV-2 in children and adolescents in Delhi, India, from January to October 2021: a repeated cross-sectional analysis.

OBJECTIVES: The aim of this study was to assess changes in the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglobulin G (IgG) seroprevalence among children and adolescents in Delhi, India from January 2021 to October 2021. METHODS: This was a repeated cross-sectional analysis of participants aged 5 to 17 years from 2 SARS-CoV-2 seroprevalence surveys conducted in Delhi, India during January 2021 and September to October 2021. Anti-SARS-CoV-2 IgG antibodies were detected by using the VITROS assay (90% sensitivity, 100% specificity). RESULTS: The seroprevalence among 5- to 17-year-old school-age children and adolescents increased from 52.8% (95% confidence interval [CI], 51.3%-54.3%) in January 2021 to 81.8% (95% CI, 80.9%-82.6%) in September to October 2021. The assay-adjusted seroprevalence was 90.8% (95% CI, 89.8%-91.7%). Seropositivity positively correlated with participants' age (p<0.001), but not sex (p=0.388). A signal to cut-off ratio ≥4.00, correlating with the presence of neutralization antibodies, was observed in 4,814 (57.9%) participants. CONCLUSION: The high percentage of seroconversion among children and adolescents indicates the presence of natural infection-induced immunity from past exposure to the SARS-CoV-2 virus. However, the lack of hybrid immunity and the concomitant likelihood of lower levels of neutralization antibodies than in adults due to the absence of vaccination warrants careful monitoring and surveillance of infection risk and disease severity from newer and emergent variants.

Inactivated whole-virion vaccine BBV152/Covaxin elicits robust cellular immune memory to SARS-CoV-2 and variants of concern.

BBV152 is a whole-virion inactivated vaccine based on the Asp614Gly variant. BBV152 is the first alum-imidazoquinolin-adjuvanted vaccine authorized for use in large populations. Here we characterized the magnitude, quality and persistence of cellular and humoral memory responses up to 6 months post vaccination. We report that the magnitude of vaccine-induced spike and nucleoprotein antibodies was comparable with that produced after infection. Receptor binding domain-specific antibodies declined against variants in the order of Alpha (B.1.1.7; 3-fold), Delta (B.1.617.2; 7-fold) and Beta (B.1.351; 10-fold). However, pseudovirus neutralizing antibodies declined up to 2-fold against the Delta followed by the Beta variant (1.7-fold). Vaccine-induced memory B cells were also affected by the Delta and Beta variants. The SARS-CoV-2-specific multicytokine-expressing CD4+ T cells were found in ~85% of vaccinated individuals. Only a ~1.3-fold reduction in efficacy was observed in CD4+ T cells against the Beta variant. We found that antigen-specific CD4+ T cells were present in the central memory compartment and persisted for at least up to 6 months post vaccination. Vaccine-induced CD8+ T cells were detected in ~50% of individuals. Importantly, the vaccine was capable of inducing follicular T helper cells that exhibited B-cell help potential. These findings show that inactivated vaccine BBV152 induces robust immune memory to SARS-CoV-2 and variants of concern that persists for at least 6 months after vaccination.

Health-Seeking Behaviour for Childhood Ailments in Caregivers of Under-Five Children in an Urban Resettlement Colony in Delhi, India.

This explorative qualitative study assesses the health-seeking behaviour for childhood ailments in caregivers of under-five children in a low-income neighbourhood in Delhi, India during July-September 2021. A total of 17 caregivers (mothers) of eight male and nine female under-five children were enrolled, with the mother being the caregiver in most (94%) cases. Caregivers consulted on common childhood ailments from multiple sources, including family, neighbours, healthcare providers (both licensed and unlicensed), frontline workers, and local pharmacists. The internet was often used as a source of child health information due to its ease of access but often "confused" caregivers due to the presence of too much information. Health-seeking behaviour of caregivers for childhood ailments could range from self-medication, local pharmacist dispensing, and private and public healthcare providers. Factors that influenced preference for the healthcare facility or provider were accessibility issues (waiting time, queuing), perceived physician competence, and associated out-of-pocket expenses. Caregivers reported dissatisfaction with government health facilities because of shorter operational hours, overcrowding, suboptimal sanitation, queuing with limited seating arrangements, and occasionally discourteous health staff. Self-medication and over-the-counter use of antibiotics was high due to a lack of awareness of the challenges of antibiotic resistance or any perceived side effects. Preference for unlicensed practitioners for medical treatment was low and based on long-term familial beliefs and acceptance. However, traditional practitioners enjoyed a high level of trust in the community from shared cultural values, enjoining attenuation of the perceived non-biological agents of childhood illnesses through non-medical supernatural interventions.

Perceptions of Good Health and Impact of COVID-19 Among Adolescents in a Low-Income Urban Agglomerate in Delhi, India: A Qualitative Study.

Adolescents constitute 16% of the global population and are susceptible to adverse health and illness from substance abuse, unhealthy diet, physical inactivity, and high-risk sexual behaviors. We conducted this study to assess the perceptions of good health, health-seeking behavior, and health service utilization among adolescents living in a low-income urban neighborhood after the second wave of the COVID-19 pandemic. A total of 23 adolescents, including 12 males and 11 females, were interviewed. Adolescents' perceived body image and size considerations apart from functioning at an optimum physical capacity as the principal attributes of good health, which was possible through the intake of a healthy diet and exercise. Adolescents were likely to be aware of the addiction potential and risk of cancer from using tobacco and alcohol, but attitudes towards eschewing their use were ambivalent. Adolescents perceived themselves as lacking access to reliable, adequate, and validated sources of sexual and reproductive health information. Knowledge and utilization of adolescent health services in this area were negligible, suggestive of the need to strengthen these services and improve the program outreach.

Breakthrough Infection With Severe Acute Respiratory Syndrome Coronavirus 2 Among Healthcare Workers in Delhi: A Single-Institution Study.

Introduction This study aimed to determine the breakthrough infection rate of coronavirus disease 2019 (COVID-19) (severe acute respiratory syndrome coronavirus 2 {SARS-CoV-2}) infection in healthcare workers (HCWs) vaccinated with either BBV152 or AZD1222 (ChAdOx1-S) vaccine. Methods A cross-sectional analysis was conducted at a medical college and hospital complex in Delhi, India, through telephonic interviews among HCWs who had received at least one dose of a COVID-19 vaccine during January-March 2021. Breakthrough infections were operationally defined as the occurrence of COVID-19 infection ≥14 days after administration of two doses of either COVID-19 vaccine. Data were entered in Epidata 3.1 (Odense, Denmark: EpiData Association) (single entered) and analyzed with IBM SPSS version 25 (Armonk, NY: IBM Corp.). A p-value < 0.05 was considered statistically significant. Results We enrolled 325 HCWs with a mean (SD) age of 29.1 (9.9) years including 211 (64.9%) males and 114 (35.1%) females. A total of 37 (13.3%, 95% CI 9.8, 17.7) COVID-19 breakthrough infections were observed in the HCWs. Additionally, 20 (6.1%) non-breakthrough infections were reported in the HCWs who were vaccinated with at least a single dose of a COVID-19 vaccine, or both doses, but prior to 14 days since the administration of the second dose. Most breakthrough infections were mild without needing supplemental oxygen for recovery. Conclusion Nearly one in seven HCWs experienced a COVID-19 breakthrough infection in the present study. A history of SARS-CoV-2 natural infection followed by at least one dose of COVID-19 vaccination was associated with significant protection against breakthrough infections.

Second Wave of the COVID-19 Pandemic in Delhi, India: High Seroprevalence Not a Deterrent?

Background We report the findings of a large follow-up, community-based, cross-sectional serosurvey and correlate it with the coronavirus disease (COVID-19) test-positivity rate and the caseload observed between the peaks of the first and the second wave of the COVID-19 pandemic in Delhi, India. Methodology Individuals aged five and above were recruited from 274 wards of the state (population approximately 19.6 million) from January 11 to January 22, 2021. A total of 100 participants each were included from all wards for a net sample size of approximately 28,000. A multistage sampling technique was employed to select participants for the household serosurvey. Anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglobulin (IgG) antibodies were detected by using the VITROS® (Ortho Clinical Diagnostics, Raritan, NJ, USA) assay (90% sensitivity, 100% specificity). Results Antibody positivity was observed in 14,298 (50.76%) of 28,169 samples. The age, sex, and district population-weighted seroprevalence of the SARS-CoV-2 IgG was 50.52% (95% confidence interval [CI] = 49.94-51.10), and after adjustment for assay characteristics, it was 56.13% (95% CI = 55.49-56.77). On adjusted analysis, participants aged ≥50 years, of female gender, housewives, having ever lived in containment zones, urban slum dwellers, and diabetes or hypertensive patients had significantly higher odds of SARS-CoV-2 antibody positivity. The peak infection rate and the test-positivity rate since October 2020 were initially observed in mid-November 2020, with a subsequent steep declining trend, followed by a period of persistently low case burden lasting until the first week of March 2021. This was followed by a steady increase followed by an exponential surge in infections from April 2021 onward culminating in the second wave of the pandemic. Conclusions The presence of infection-induced immunity from SARS-CoV-2 even in more than one in two people can be ineffective in protecting the population. Despite such high seroprevalence, population susceptibility to COVID-19 can be accentuated by variants of concern having the ability for rapid transmission and depletion of antibody levels with the threat of recurrent infections, signifying the need for mass vaccination.

The seroprevalence of severe acute respiratory syndrome coronavirus 2 in Delhi, India: a repeated population-based seroepidemiological study.

BACKGROUND: Three rounds of a repeated cross-sectional serosurvey to estimate the change in seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were conducted from August to October 2020 in the state of Delhi, India, in the general population ≥5 y of age. METHODS: The selection of participants was through a multistage sampling design from all 11 districts and 280 wards of the city-state, with multistage allocation proportional to population size. The blood samples were screened using immunoglobulin G (IgG) enzyme-linked immunosorbent assay kits. RESULTS: We observed a total of 4267 (N=150 46), 4311 (N=17 409) and 3829 (N=15 015) positive tests indicative of the presence of IgG antibody to SARS-CoV-2 during the August, September and October 2020 serosurvey rounds, respectively. The adjusted seroprevalence declined from 28.39% (95% confidence interval [CI] 27.65 to 29.14) in August to 24.08% (95% CI 23.43 to 24.74) in September and 24.71% (95% CI 24.01 to 25.42) in October. On adjusted analysis, participants with lower per capita income, living in slums or overcrowded households and those with diabetes comorbidity had significantly higher statistical odds of having antibody positivity (p<0.01). CONCLUSIONS: Nearly one in four residents in Delhi, India ≥5 y of age had the SARS-CoV-2 infection during August-October 2020.

Longitudinal Serology of SARS-CoV-2-Infected Individuals in India: A Prospective Cohort Study.

Clinical and epidemiological characteristics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are now widely available, but there are few data regarding longitudinal serology in large cohorts, particularly those from low-income and middle-income countries. We established an ongoing prospective cohort of 3,840 SARS-CoV-2-positive individuals according to RT-PCR in the Delhi-National Capital Region of India to document clinical and immunological characteristics during illness and convalescence. The immunoglobulin G (IgG) responses to the receptor binding domain (RBD) and nucleocapsid were assessed at 0 to 7 days, 10 to 28 days, and 6 to 10 weeks after infection. The clinical predictors of seroconversion were identified by multivariable regression analysis. The seroconversion rates during the postinfection windows of 0 to 7 days, 10 to 28 days, and 6 to 10 weeks were 46%, 84.7%, and 85.3%, respectively (N = 743). The proportion with a serological response increased with the severity of coronavirus disease 2019 (COVID-19). All participants with severe disease, 89.6% with mild to moderate infection, and 77.3% of asymptomatic participants had IgG antibodies to the RBD antigen. The threshold values for the nasopharyngeal viral RNA RT-PCR of a subset of asymptomatic and symptomatic seroconverters were comparable (P = 0.48) to those of nonseroconverters (P = 0.16) (N = 169). This is the first report of longitudinal humoral immune responses to SARS-CoV-2 over a period of 10 weeks in South Asia. The low seropositivity of asymptomatic participants and differences between assays highlight the importance of contextualizing the understanding of population serosurveys.

Seroprevalence of antibodies to SARS-CoV-2 and predictors of seropositivity among employees of a teaching hospital in New Delhi, India.

OBJECTIVE: Healthcare workers (HCWs) are at a high risk of contracting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) due to the increased likelihood of clinical exposure during patient management. The study objective was to determine the seroprevalence of antibodies to SARS-CoV-2 and its predictors among hospital employees. METHODS: The cross-sectional study was conducted at a teaching hospital from August 2020 to September 2020 among 1,401 employees, including 1,217 HCWs, in New Delhi, India. The serum samples were examined for immunoglobulin G (IgG) antibodies to SARS-CoV-2 using the COVID Kavach-Anti-SARS-CoV-2 IgG Antibody Detection enzyme-linked immunosorbent assay kit. Data were collected electronically using the EpiCollect mobile platform. A p < 0.05 was considered to indicate statistical significance. RESULTS: A total of 169 participants (12.1%) had detectable IgG antibodies to SARS-CoV-2. The highest seropositivity rate was observed in the administrative staff (20.1%), while it was lowest among medical doctors (5.5%, p < 0.001). Male sex and ever having lived in a containment zone were independently associated with past infection with SARS-CoV-2. CONCLUSION: The seroprevalence of SARS-CoV-2 infection in health workers may be lower than in the general population in New Delhi. However, nonpharmaceutical interventions were not associated with a reduction in the risk of acquisition of SARS-CoV-2.

Development of a Fast SARS-CoV-2 IgG ELISA, Based on Receptor-Binding Domain, and Its Comparative Evaluation Using Temporally Segregated Samples From RT-PCR Positive Individuals.

SARS-CoV-2 antibody detection assays are crucial for gathering seroepidemiological information and monitoring the sustainability of antibody response against the virus. The SARS-CoV-2 Spike protein's receptor-binding domain (RBD) is a very specific target for anti-SARS-CoV-2 antibodies detection. Moreover, many neutralizing antibodies are mapped to this domain, linking antibody response to RBD with neutralizing potential. Detection of IgG antibodies, rather than IgM or total antibodies, against RBD is likely to play a larger role in understanding antibody-mediated protection and vaccine response. Here we describe a rapid and stable RBD-based IgG ELISA test obtained through extensive optimization of the assay components and conditions. The test showed a specificity of 99.79% (95% CI: 98.82-99.99%) in a panel of pre-pandemic samples (n = 470) from different groups, i.e., pregnancy, fever, HCV, HBV, and autoantibodies positive. Test sensitivity was evaluated using sera from SARS-CoV-2 RT-PCR positive individuals (n = 312) and found to be 53.33% (95% CI: 37.87-68.34%), 80.47% (95% CI: 72.53-86.94%), and 88.24% (95% CI: 82.05-92.88%) in panel 1 (days 0-13), panel 2 (days 14-20) and panel 3 (days 21-27), respectively. Higher sensitivity was achieved in symptomatic individuals and reached 92.14% (95% CI: 86.38-96.01%) for panel 3. Our test, with a shorter runtime, showed higher sensitivity than parallelly tested commercial ELISAs for SARS-CoV-2-IgG, i.e., Euroimmun and Zydus, even when equivocal results in the commercial ELISAs were considered positive. None of the tests, which are using different antigens, could detect anti-SARS-CoV-2 IgGs in 10.5% RT-PCR positive individuals by the fourth week, suggesting the lack of IgG response.