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1.
The Lancet Regional Health - Americas ; 8:100182, 2022.
Article in English | ScienceDirect | ID: covidwho-1620909

ABSTRACT

Summary Background As SARS-CoV-2 vaccines are administered worldwide, the COVID-19 pandemic continues to exact significant human and economic costs. Mass testing of unvaccinated individuals followed by isolation of positive cases can substantially mitigate risks and be tailored to local epidemiological conditions to ensure cost effectiveness. Methods Using a multi-scale model that incorporates population-level SARS-CoV-2 transmission and individual-level viral load kinetics, we identify the optimal frequency of proactive SARS-CoV-2 testing, depending on the local transmission rate and proportion immunized. Findings Assuming a willingness-to-pay of US$100,000 per averted year of life lost (YLL) and a price of $10 per test, the optimal strategy under a rapid transmission scenario (Re ∼ 2.5) is daily testing until one third of the population is immunized and then weekly testing until half the population is immunized, combined with a 10-day isolation period of positive cases and their households. Under a low transmission scenario (Re ∼ 1.2), the optimal sequence is weekly testing until the population reaches 10% partial immunity, followed by monthly testing until 20% partial immunity, and no testing thereafter. Interpretation Mass proactive testing and case isolation is a cost effective strategy for mitigating the COVID-19 pandemic in the initial stages of the global SARS-CoV-2 vaccination campaign and in response to resurgences of vaccine-evasive variants. Funding

3.
EMBO Mol Med ; : e15227, 2022 Jan 06.
Article in English | MEDLINE | ID: covidwho-1614347

ABSTRACT

The SARS-CoV-2 Delta (B.1.617.2) variant is capable of infecting vaccinated persons. An open question remains as to whether deficiencies in specific vaccine-elicited immune responses result in susceptibility to vaccine breakthrough infection. We investigated 55 vaccine breakthrough infection cases (mostly Delta) in Singapore, comparing them against 86 vaccinated close contacts who did not contract infection. Vaccine breakthrough cases showed lower memory B cell frequencies against SARS-CoV-2 receptor binding domain (RBD). Compared to plasma antibodies, antibodies secreted by memory B cells retained a higher fraction of neutralizing properties against the Delta variant. Inflammatory cytokines including IL-1ß and TNF were lower in vaccine breakthrough infections than primary infection of similar disease severity, underscoring the usefulness of vaccination in preventing inflammation. This report highlights the importance of memory B cells against vaccine breakthrough, and suggests that lower memory B cell levels may be a correlate of risk for Delta vaccine breakthrough infection.

4.
Frontiers in public health ; 9, 2021.
Article in English | EuropePMC | ID: covidwho-1610585
5.
J Pediatr Hematol Oncol ; 2021 Mar 31.
Article in English | MEDLINE | ID: covidwho-1608558

ABSTRACT

Data regarding the epidemiologic characteristics and clinical features of pediatric hematological patients are limited in this corona virus disease 2019 (COVID-19) crisis. We investigated the status of 113 pediatric hematological patients in Wuhan union hospital during the COVID-19 pandemic from January 23 to March 10, 2020. All the patients had routine blood and biochemical examination, as well as chest computed tomography scans, and the nucleic acid, immunoglobulin G-immunoglobulin M combined antibodies tests for SARS-CoV-2. After admission, all patients were single-room isolated for 5 to 7 days. The results showed that only 1 (0.88%) child with leukemia was confirmed to have SARS-CoV-2 infection and 15 (13.2%) children were considered as suspected cases. Comparing to the nonsuspected patients, the suspected cases had lower white blood cell count, hemoglobin level, neutrophil count, serum calcium ion level and serum albumin concentration, as well as higher levels of C-reactive protein. All the suspected cases were ruled out of SARS-CoV-2 infection by twice negative tests for the virus. Therefore, the incidence of SARS-CoV-2 infection in hematological malignancy children was low during the COVID-19 pandemic in China. COVID-19 got early detected and the virus spread out in the ward was effectively blocked by increasing test frequency and using single-room isolation for 5 to 7 days after admission.

7.
Fermentation ; 7(4):286, 2021.
Article in English | ProQuest Central | ID: covidwho-1599315

ABSTRACT

Paper mulberry (Broussonetia papyrifera) is widely ensiled to feed sheep in southwestern China, as unconventional woody forage. Feeding lambs with paper mulberry silage (PMS) may improve certain feeding characteristics, thereby affecting the growth performance and meat quality. The aim of this study is to investigate the effects of four diets of PMS on growth performance, rumen microbial composition, and muscle fatty acids profile in Hu lambs. The results showed that 30% and 40% PMS increased the dry matter intake and average daily gain of Hu lambs compared to the control group. PMS30 and PMS40 increased the content of C24:1, and PMS40 increased the content of C20:5n-3. The content of microbial protein (MCP) was higher in PMS40 than in others, but PMS30 and PMS40 reduced the total volatile fatty acid in rumen. PMS30 significantly increased the ratio of acetic acid to propionic acid. The abundance of ruminal Christensenellaceae_R-7_group and norank_f_Eubacterium_coprostanoligenes_group was significantly higher in PMS30 and PMS40 groups. Moreover, Christensenellaceae_R-7_group had a significant positive correlation with n3-polyunsaturated fatty acid. PMS40 might lead to a relatively high content of unsaturated fatty acids in longissimus dorsi muscle by increasing the relative abundance of Christensenellaceae_R-7_group in rumen.

8.
IEEE J Biomed Health Inform ; PP2021 Dec 31.
Article in English | MEDLINE | ID: covidwho-1599120

ABSTRACT

This paper presents a novel Lasso Logistic Regression model based on feature-based time series data to determine disease severity and when to administer drugs or escalate intervention procedures in patients with coronavirus disease 2019 (COVID-19). Advanced features were extracted from highly enriched and time series vital sign data of hospitalized COVID-19 patients, including oxygen saturation readings, and with a combination of patient demographic and comorbidity information, as inputs into the dynamic feature-based classification model. Such dynamic combinations brought deep insights to guide clinical decision-making of complex COVID-19 cases, including prognosis prediction, timing of drug administration, admission to intensive care units, and application of intervention procedures like ventilation and intubation. The COVID-19 patient classification model was developed utilizing 900 hospitalized COVID-19 patients in a leading multi-hospital system in Texas, United States. By providing mortality prediction based on time-series physiologic data, demographics, and clinical records of individual COVID-19 patients, the dynamic feature-based classification model can be used to improve efficacy of the COVID-19 patient treatment, prioritize medical resources, and reduce casualties. The uniqueness of our model is that it is based on just the first 24 hours of vital sign data such that clinical interventions can be decided early and applied effectively. Such a strategy could be extended to prioritize resource allocations and drug treatment for future pandemic events.

9.
Int J Environ Res Public Health ; 18(24)2021 12 09.
Article in English | MEDLINE | ID: covidwho-1592647

ABSTRACT

Since the 1970s, health communication (HC) has attracted widespread attention from practitioners and researchers in various fields in China, leading to the production of a vast array of literature. In order to reveal the current state, popular themes, and research frontiers of HC research, this study employed the CiteSpace software to conduct a comprehensive review based on 1505 HC publications from 1992 to 2021 retrieved from the China National Knowledge Infrastructure (CNKI) database. The results demonstrated that (1) the number of HC publications has experienced an annual increase over the past 20 years, albeit with certain inverted S-shaped fluctuations and (2) the most prolific authors mainly included Wang L.Y., Zhang Z.L., and Wang Y.L., while well-known universities played a leading role in HC research in China. A significant finding was that a stable core group of authors or institutional has been not formed in the HC field. Furthermore, (3) research hotspots included health education, new media, health literacy, health information, animal husbandry and veterinary medicine (AHVM), the doctor-patient relationship, and public health emergencies. Additionally, the development of the field could be divided into four stages, indicating a significant shift in HC research from focusing on medicine and public health issues towards communication issues. Finally, (4) new research frontiers have mainly included the WeChat official account and Health China.


Subject(s)
Health Communication , Animals , Bibliometrics , China , Humans , Physician-Patient Relations , Software
10.
Front Immunol ; 12: 782731, 2021.
Article in English | MEDLINE | ID: covidwho-1581325

ABSTRACT

The SARS-CoV-2 and its variants are still hitting the world. Ever since the outbreak, neurological involvements as headache, ageusia, and anosmia in COVID-19 patients have been emphasized and reported. But the pathogenesis of these new-onset neurological manifestations in COVID-19 patients is still obscure and controversial. As difficulty always lay in the diagnosis of neurological infection, current reports to validate the presence of SARS-CoV-2 in cerebrospinal fluid (CSF) almost relied on the basic methods and warranted improvement. Here we reported a case series of 8 patients with prominent new-onset neurological manifestations, who were screened out from a patch of 304 COVID-19 confirmed patients. Next-generation sequencing (NGS) and proteomics were conducted in the simultaneously obtained CSF and serum samples of the selected patients, with three non-COVID-19 patients with matched demographic features used as the controls for proteomic analysis. SARS-CoV-2 RNA was detected in the CSF of four COVID-19 patients and was suspicious in the rest four remaining patients by NGS, but was negative in all serum samples. Proteomic analysis revealed that 185 and 59 proteins were differentially expressed in CSF and serum samples, respectively, and that only 20 proteins were shared, indicating that the proteomic changes in CSF were highly specific. Further proteomic annotation highlighted the involvement of complement system, PI3K-Akt signaling pathway, enhanced cellular interaction, and macrophages in the CSF proteomic alterations. This study, equipped with NGS and proteomics, reported a high detection rate of SARS-CoV-2 in the CSF of COVID-19 patients and the proteomic alteration of CSF, which would provide insights into understanding the pathological mechanism of SARS-CoV-2 CNS infection.


Subject(s)
COVID-19/cerebrospinal fluid , Central Nervous System Diseases/virology , Cerebrospinal Fluid/metabolism , Cerebrospinal Fluid/virology , RNA, Viral/cerebrospinal fluid , Adult , Aged , Aged, 80 and over , Female , High-Throughput Nucleotide Sequencing , Humans , Male , Middle Aged , Proteomics , SARS-CoV-2 , Sequence Analysis, RNA
11.
Preprint | EuropePMC | ID: ppcovidwho-296939

ABSTRACT

Efficient COVID-19 vaccines have been developed in record time. Here, we present findings from a comprehensive and integrated analysis of multiple compartments of the memory immune response in 312 individuals vaccinated with the BNT162b2 mRNA vaccine. Two vaccine doses induced high antibody and T cell responses in most individuals. However, antibody recognition of the Spike protein of delta variant was less efficient than that of the Wuhan strain. Age stratified analyses identified a group of low antibody responders where individuals ≥ 60 years were overrepresented. Waning of the antibody and cellular responses was observed in 30% of the vaccinees after six months. However, age did not influence the waning of these responses. Taken together, while individuals ≥ 60 years old took longer to acquire vaccine-induced immunity, they develop more sustained acquired immunity at six months post-vaccination. However, the higher proportion of older individuals in the group of antibody low responders and the lower antibody reactivity the Delta variant call for a booster immunization to increase immune responses and protection.

12.
Preprint | EuropePMC | ID: ppcovidwho-296635

ABSTRACT

Superspreading in transmission is a feature of SARS-CoV-2 transmission. We conducted a systematic review and meta-analysis on globally reported dispersion parameters of SARS-CoV-2. The pooled estimate was 0.55 (95% CI: 0.30, 0.79). The study location and method were found to be important drivers for its diversity.

13.
Lancet Infect Dis ; 2021 Dec 07.
Article in English | MEDLINE | ID: covidwho-1565673

ABSTRACT

BACKGROUND: Large-scale vaccination against COVID-19 is being implemented in many countries with CoronaVac, an inactivated vaccine. We aimed to assess the immune persistence of a two-dose schedule of CoronaVac, and the immunogenicity and safety of a third dose of CoronaVac, in healthy adults aged 18 years and older. METHODS: In the first of two single-centre, double-blind, randomised, placebo-controlled phase 2 clinical trials, adults aged 18-59 years in Jiangsu, China, were initially allocated (1:1) into two vaccination schedule cohorts: a day 0 and day 14 vaccination cohort (cohort 1) and a day 0 and day 28 vaccination cohort (cohort 2); each cohort was randomly assigned (2:2:1) to either a 3 µg dose or 6 µg dose of CoronaVac or a placebo group. Following a protocol amendment on Dec 25, 2020, half of the participants in each cohort were allocated to receive an additional dose 28 days (window period 30 days) after the second dose, and the other half were allocated to receive a third dose 6 months (window period 60 days) after the second dose. In the other phase 2 trial, in Hebei, China, participants aged 60 years and older were assigned sequentially to receive three injections of either 1·5 µg, 3 µg, or 6 µg of vaccine or placebo, administered 28 days apart for the first two doses and 6 months (window period 90 days) apart for doses two and three. The main outcomes of the study were geometric mean titres (GMTs), geometric mean increases (GMIs), and seropositivity of neutralising antibody to SARS-CoV-2 (virus strain SARS-CoV-2/human/CHN/CN1/2020, GenBank accession number MT407649.1), as analysed in the per-protocol population (all participants who completed their assigned third dose). Our reporting is focused on the 3 µg groups, since 3 µg is the licensed formulation. The trials are registered with ClinicalTrials.gov, NCT04352608 and NCT04383574. FINDINGS: 540 (90%) of 600 participants aged 18-59 years were eligible to receive a third dose, of whom 269 (50%) received the primary third dose 2 months after the second dose (cohorts 1a-14d-2m and 2a-28d-2m) and 271 (50%) received a booster dose 8 months after the second dose (cohorts 1b-14d-8m and 2b-28d-8m). In the 3 µg group, neutralising antibody titres induced by the first two doses declined after 6 months to near or below the seropositive cutoff (GMT of 8) for cohort 1b-14d-8m (n=53; GMT 3·9 [95% CI 3·1-5·0]) and for cohort 2b-28d-8m (n=49; 6·8 [5·2-8·8]). When a booster dose was given 8 months after a second dose, GMTs assessed 14 days later increased to 137·9 (95% CI 99·9-190·4) for cohort 1b-14d-8m and 143·1 (110·8-184·7) 28 days later for cohort 2b-28d-8m. GMTs moderately increased following a primary third dose, from 21·8 (95% CI 17·3-27·6) on day 28 after the second dose to 45·8 (35·7-58·9) on day 28 after the third dose in cohort 1a-14d-2m (n=54), and from 38·1 (28·4-51·1) to 49·7 (39·9-61·9) in cohort 2a-28d-2m (n=53). GMTs had decayed to near the positive threshold by 6 months after the third dose: GMT 9·2 (95% CI 7·1-12·0) in cohort 1a-14d-2m and 10·0 (7·3-13·7) in cohort 2a-28d-2m. Similarly, in adults aged 60 years and older who received booster doses (303 [87%] of 350 participants were eligible to receive a third dose), neutralising antibody titres had declined to near or below the seropositive threshold by 6 months after the primary two-dose series. A third dose given 8 months after the second dose significantly increased neutralising antibody concentrations: GMTs increased from 42·9 (95% CI 31·0-59·4) on day 28 after the second dose to 158·5 (96·6-259·2) on day 28 following the third dose (n=29). All adverse reactions reported within 28 days after a third dose were of grade 1 or 2 severity in all vaccination cohorts. There were three serious adverse events (2%) reported by the 150 participants in cohort 1a-14d-2m, four (3%) by 150 participants from cohort 1b-14d-8m, one (1%) by 150 participants in each of cohorts 2a-28d-2m and 2b-28d-8m, and 24 (7%) by 349 participants from cohort 3-28d-8m. INTERPRETATION: A third dose of CoronaVac in adults administered 8 months after a second dose effectively recalled specific immune responses to SARS-CoV-2, which had declined substantially 6 months after two doses of CoronaVac, resulting in a remarkable increase in the concentration of antibodies and indicating that a two-dose schedule generates good immune memory, and a primary third dose given 2 months after the second dose induced slightly higher antibody titres than the primary two doses. FUNDING: National Key Research and Development Program, Beijing Science and Technology Program, and Key Program of the National Natural Science Foundation of China. TRANSLATION: For the Mandarin translation of the abstract see Supplementary Materials section.

14.
Int J Environ Res Public Health ; 18(23)2021 Nov 27.
Article in English | MEDLINE | ID: covidwho-1559545

ABSTRACT

The challenging labor market conditions concomitant with economic globalization and advanced technology have made youth career development competency (YCDC)-young people's ability to navigate transitions through education into productive and meaningful employment-especially important. The present study aims to develop a holistic instrument to measure YCDC in Hong Kong, which has rarely been investigated in past studies. The sample consisted of 682 youths aged 15-29 years (387 male, mean age = 19.5 years) in Hong Kong. Exploratory factor analysis of the 17-item YCDC scale resulted in four competence factors-engagement, self-understanding, career and pathway exploration, and planning and career management-which accounted for 78.95% of the total variance. The final confirmatory factor analysis results indicated good model fit (CFI = 0.96, TLI = 0.95, RMSEA = 0.06, 90% CI (0.05, 0.07), SRMR = 0.03) and good factor loadings (0.78-0.91). Moreover, the results demonstrated a satisfactory internal consistency of subscales (0.89-0.93). Subgroup consistency across subsamples categorized by gender, age, and years of residence in Hong Kong was also demonstrated. In addition, correlations between the YCDC scale and subscales with other career-related and psychosocial outcomes (i.e., career outcome expectancy, career adaptability, civic engagement, social contribution, and social integration) showed good concurrent validity. The results indicated that the YCDC scale is a valid and reliable tool for measuring career development competence among youth in the Hong Kong context. Its development sheds light on how career professionals can holistically assess young people's navigation competence during their school-to-work transitions.

15.
Biosens Bioelectron ; 199: 113868, 2022 Mar 01.
Article in English | MEDLINE | ID: covidwho-1561218

ABSTRACT

COVID-19 vaccination efficacy depends on serum levels of the neutralizing antibodies (NAs) specific to the receptor-binding domain of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein. Therefore, a high-throughput rapid assay capable of measuring the total SARS-CoV-2 NA level is urgently needed for COVID-19 serodiagnosis, convalescent plasma therapy, vaccine development, and assessment. Here, we developed a novel nanoplasmonic immunosorbent assay (NanoPISA) platform for one-step rapid quantification of SARS-CoV-2 NAs in clinical serum samples for high-throughput evaluation of COVID-19 vaccine effectiveness. The NanoPISA platform enhanced by the use of nanoporous hollow gold nanoparticle coupling was able to detect SARS-CoV-2 NAs with a limit of detection of 0.2 pM within 15 min without washing steps. The one-step NanoPISA for SARS-CoV-2 NA detection in clinical specimens yielded good results, comparable with those obtained in the gold-standard seroneutralization test and the surrogate virus-neutralizing enzyme-linked immunosorbent assay. Collectively, the one-step NanoPISA might be a rapid and high-throughput NA-quantification platform for evaluating the effectiveness of COVID-19 vaccines.


Subject(s)
Biosensing Techniques , COVID-19 , Metal Nanoparticles , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/therapy , COVID-19 Vaccines , Gold , Humans , Immunization, Passive , SARS-CoV-2 , Vaccination
16.
Int J Infect Dis ; 2021 Dec 02.
Article in English | MEDLINE | ID: covidwho-1549834

ABSTRACT

IMPORTANCE: Since January 2020, Singapore has implemented comprehensive measures to suppress SARS-CoV-2. Despite this, the country has experienced contrasting epidemics, with limited transmission in the community and explosive outbreaks in migrant worker dormitories. OBJECTIVE: To estimate SARS-CoV-2 infection incidence among migrant workers and the general population in Singapore. DESIGN: Prospective serological cohort studies. SETTING: Two cohort studies in a migrant worker dormitory and in the general population in Singapore. PARTICIPANTS: We followed up 478 residents of a SARS-CoV-2 affected migrant worker dormitory between May and July 2020, collecting blood samples at recruitment and after two and six weeks. We also recruited 937 community-dwelling adult Singapore residents for whom pre-pandemic sera were available. These individuals also provided a serum sample at recruitment in November/December 2020. EXPOSURE: Exposure to SARS-CoV-2 in a densely populated migrant worker dormitory and in the general population. MAIN OUTCOMES AND MEASURES: The main outcome measures were the incidence of SARS-CoV-2 infection in migrant workers and in the general population, as determined by the detection of neutralising antibodies against SARS-CoV-2 and adjusting for assay sensitivity and specificity using a Bayesian modelling framework. RESULTS: We found no evidence of community SARS-CoV-2 exposure in Singapore prior to September 2019. We estimated that <2 per 1000 adult residents in the community were infected with SARS-CoV-2 in 2020 (cumulative seroprevalence: 0.16% (95% CrI: 0.008% - 0.72%). Comparison with comprehensive national case notification data suggests that around 1 in 4 infections in the general population is associated with symptoms. In contrast, in the migrant worker cohort, nearly two-thirds had been infected by July 2020 (cumulative seroprevalence: 63.8% (95% CrI: 57.9% - 70.3%); no symptoms were reported in almost all of these infections. CONCLUSIONS AND RELEVANCE: Our findings demonstrate that SARS-CoV-2 suppression is possible with strict and rapid implementation of border restrictions, case isolation, contact tracing, quarantining and social distancing measures. However, the risk of large-scale epidemics in densely-populated environments requires specific consideration in preparedness planning. Prioritisation of these settings in vaccination strategies should minimise risk of future resurgences and potential spillover of transmission to the wider community.

18.
J Med Virol ; 93(12): 6506-6511, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1544294

ABSTRACT

Anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglouilin G (IgG) and immunoglouilin M (IgM) antibodies have been widely used to assist clinical diagnosis. Our previous study reported a discrepancy in SARS-CoV-2 antibody response between male and female coronavirus disease 2019 (COVID-19) patients. However, the duration and discrepancy between ages as well as sexes of SARS-CoV-2 antibody in convalescent COVID-19 patients have not been clarified. In this study, a total of 538 health-examination individuals who were confirmed with SARS-CoV-2 infection a year ago were enrolled. Blood samples were collected and detected for IgM and IgG antibodies. Among these convalescent patients, 12.80% were detected positive for IgM antibodies. The positive rates for IgM antibody were close between sexes: for males, this is 9.17% and for females 13.75%. However, the IgG antibody was detected positive in as much as 82.90% convalescent patients and the positive rates were nearly the same between males (82.57%) and females (82.98%). Besides this, the level of IgM and IgG antibodies showed no difference between male and female convalescent patients. The level of IgG antibodies showed a significant difference between ages. The elder patients (over 35 years old) maintained a higher level of IgG antibody than the younger patients (under or equal 35 years old) after recovering for 1 year. In addition, IgG antibody was more vulnerable to disappear in younger patients than in elder patients. Overall, our study identified over 1-year duration of SARS-CoV-2 antibody and age difference of IgG antibody response in convalescent COVID-19 patients. These findings may provide new insights into long-term humoral immune response, vaccines efficacy and age-based personalized vaccination strategies.


Subject(s)
Antibodies, Viral/blood , Immunoglobulin G/blood , Immunoglobulin M/blood , SARS-CoV-2/immunology , Adult , Age Factors , Aged , COVID-19/immunology , Coronavirus Nucleocapsid Proteins/immunology , Female , Humans , Male , Middle Aged , Phosphoproteins/immunology , Sex Factors , Spike Glycoprotein, Coronavirus/immunology , Young Adult
19.
Anal Chem ; 2021 Nov 30.
Article in English | MEDLINE | ID: covidwho-1541110

ABSTRACT

With the outbreak of COVID-19, which is fast transmitting and highly contagious, the development of rapid, highly specific, and sensitive detection kits has become a research hotspot. The existing assay methods for SARS-CoV-2 are mainly based on enzymatic reactions, which require expensive reagents, hindering popular use, especially in resource-constrained areas. Herein, we propose an aptamer-based method for the assay of SARS-CoV-2 via binding of the spike protein using functionalized biomimetic nanochannels. To get the analogous effect of human ACE2, a receptor for the spike protein, the aptamer to bind to the spike S1 protein has been first screened by a SELEX technique and then immobilized on the previously prepared nanochannels. In the presence of SARS-CoV-2, the changes in steric hindrance and charge density on the surface of the nanochannels will affect the ion transport, along with a rapid electrochemical response. Our method has been successfully applied to detect the viral particles in clinical pharyngeal swab specimens in one step without sample treatment. We expect this rapid, reagent-free, and sensitive assay method to be developed as a useful tool for diagnosing COVID-19.

20.
Emerg Microbes Infect ; 10(1): 2141-2150, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1532382

ABSTRACT

BACKGROUND: We studied humoral and cellular responses against SARS-CoV-2 longitudinally in a homogeneous population of healthy young/middle-aged men of South Asian ethnicity with mild COVID-19. METHODS: In total, we recruited 994 men (median age: 34 years) post-COVID-19 diagnosis. Repeated cross-sectional surveys were conducted between May 2020 and January 2021 at six time points - day 28 (n = 327), day 80 (n = 202), day 105 (n = 294), day 140 (n = 172), day 180 (n = 758), and day 280 (n = 311). Three commercial assays were used to detect anti-nucleoprotein (NP) and neutralizing antibodies. T cell response specific for Spike, Membrane and NP SARS-CoV-2 proteins was tested in 85 patients at day 105, 180, and 280. RESULTS: All serological tests displayed different kinetics of progressive antibody reduction while the frequency of T cells specific for different structural SARS-CoV-2 proteins was stable over time. Both showed a marked heterogeneity of magnitude among the studied cohort. Comparatively, cellular responses lasted longer than humoral responses and were still detectable nine months after infection in the individuals who lost antibody detection. Correlation between T cell frequencies and all antibodies was lost over time. CONCLUSION: Humoral and cellular immunity against SARS-CoV-2 is induced with differing kinetics of persistence in those with mild disease. The magnitude of T cells and antibodies is highly heterogeneous in a homogeneous study population. These observations have implications for COVID-19 surveillance, vaccination strategies, and post-pandemic planning.


Subject(s)
Antibodies, Viral/blood , COVID-19/immunology , SARS-CoV-2/immunology , T-Lymphocytes/immunology , Adult , Antibodies, Neutralizing/blood , Cross-Sectional Studies , Humans , Male , Nucleocapsid Proteins/immunology
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