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Background: There is a lack of research evidence on the quantitative relationship between symptom burden and health care seeking among individuals with presumptive tuberculosis (TB). Methods: Data were derived from a cross-sectional population-based TB survey conducted between February 2021 and July 2022 in 32 districts of India. Eligible and consented participants (age >15 years) underwent TB symptom screening and history elicitation. Fairlie decomposition analysis was used to estimate the net differences in health care seeking due to varied symptom burden-from 1+ burden (>1 symptom) to 4+ burden (>4 symptoms)-and decomposed by observable covariates based on logit models with 95% CIs. Results: Of the 130 932 individuals surveyed, 9540 (7.3%) reported at least 1 recent TB symptom, of whom 2678 (28.1%; 95% CI, 27.1%-28.9%) reportedly sought health care. The net differences in health care seeking among persons with symptom burden 1+ to 4+ ranged from 6.6 percentage points (95% CI, 4.8-8.4) to 7.7 (95% CI, 5.2-10.2) as compared with persons with less symptom burden. The presence of expectoration, fatigue, and loss of appetite largely explained health care seeking (range, 0.9-3.1 percentage points [42.89%-151.9%]). The presence of fever, cough, past TB care seeking, weight loss, and chest pain moderately explained (range, 5.3%-25.3%) health care seeking. Conclusions: Increased symptom burden and symptoms other than the commonly emphasized cough and fever largely explained health care seeking. Orienting TB awareness and risk communications toward symptom burden and illness perceptions could help address population gaps in health care seeking for TB.
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Programas de Rastreamento , Tuberculose Pulmonar , Humanos , Índia/epidemiologia , Estudos Transversais , Prevalência , Adulto , Masculino , Feminino , Tuberculose Pulmonar/epidemiologia , Tuberculose Pulmonar/diagnóstico , Pessoa de Meia-Idade , Programas de Rastreamento/métodos , Adulto Jovem , Adolescente , Radiografia Torácica , Criança , Idoso , Pré-EscolarRESUMO
To reduce TB deaths, Tamil Nadu, a southern Indian state, implemented the first state-wide differentiated TB care strategy starting April 2022. Triage-positive severely ill patients are prioritised for comprehensive assessment and inpatient care. Routine program data during October-December 2022 revealed that documentation of total score after comprehensive assessment was available in only 39%, possibly indicating poor quality of comprehensive assessment. We confirmed this using operational research. The case record form to record comprehensive assessment was used only in 26% and among these, the completeness and correctness in filling out the form were sub-optimal. There is a clear need to enhance the quality of comprehensive assessments.
Depuis avril 2022, le Tamil Nadu, un État du sud de l'Inde, a mis en Åuvre la première stratégie de soins différenciés pour la TB à l'échelle de l'État afin de réduire le nombre de décès dus à la TB. Les personnes gravement malades ayant obtenu un résultat positif au triage sont prioritaires pour une évaluation complète et des soins hospitaliers. Les données du programme de routine entre octobre et décembre 2022 ont révélé que la documentation du score total après l'évaluation complète n'était disponible que dans 39% des cas, ce qui pourrait indiquer une mauvaise qualité de l'évaluation complète. Nous l'avons confirmé par le biais d'une recherche opérationnelle. Le formulaire de dossier pour enregistrer l'évaluation complète n'a été utilisé que dans 26% des cas et, parmi ceux-ci, l'exhaustivité et l'exactitude du remplissage du formulaire n'étaient pas optimales. Il est manifestement nécessaire d'améliorer la qualité de l'évaluation complète.
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BACKGROUND: Noncommunicable diseases (NCDs) account for nearly 75% of all deaths in Tamil Nadu. The government of Tamil Nadu has initiated several strategies to control NCDs under the Tamil Nadu Health Systems Reform Program (TNHSRP). We aimed to estimate the prevalence of NCD risk factors and determine the predictors of diabetes and hypertension, which will be helpful for planning and serve as a baseline for evaluating the impact of interventions. METHODS: A state-wide representative cross-sectional study was conducted among 18-69-year-old adults in Tamil Nadu in 2020. The study used a multi-stage sampling method to select the calculated sample size of 5780. We adapted the study tools based on WHO's STEPS surveillance methodology. We collected information about sociodemographic factors, NCD risk factors and measured blood pressure and fasting capillary blood glucose. The predictors of diabetes and hypertension were calculated using generalised linear models with 95% confidence intervals (95% CI). RESULTS: Due to the COVID-19 pandemic lockdown, we could cover 68% (n = 3800) of the intended sample size. Among the eligible individuals surveyed (n = 4128), we had a response rate of 92%. The mean age of the study participants was 42.8 years, and 51% were women. Current tobacco use was prevalent in 40% (95% CI: 33.7-40.0) of men and 7.9% (95% CI: 6.4-9.8) of women. Current consumption of alcohol was prevalent among 39.1% (95% CI: 36.4-42.0) of men. Nearly 28.5% (95% CI: 26.7-30.4) of the study participants were overweight, and 11.4% (95% CI: 10.1-12.7) were obese. The prevalence of hypertension was 33.9% (95% CI: 32.0-35.8), and that of diabetes was 17.6% (95% CI: 16.1-19.2). Older age, men, and obesity were independently associated with diabetes and hypertension. CONCLUSION: The burden of NCD risk factors like tobacco use, and alcohol use were high among men in the state of Tamil Nadu. The prevalence of other risk factors like physical inactivity, raised blood pressure and raised blood glucose were also high in the state. The state should further emphasise measures that reduce the burden of NCD risk factors. Policy-based and health system-based interventions to control NCDs must be a high priority for the state.
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Diabetes Mellitus , Hipertensão , Doenças não Transmissíveis , Humanos , Masculino , Pessoa de Meia-Idade , Adulto , Feminino , Doenças não Transmissíveis/epidemiologia , Fatores de Risco , Prevalência , Estudos Transversais , Idoso , Hipertensão/epidemiologia , Índia/epidemiologia , Adolescente , Adulto Jovem , Diabetes Mellitus/epidemiologia , COVID-19/epidemiologiaRESUMO
Background: Non-communicable diseases (NCDs) are the leading cause of morbidity and mortality in India, necessitating development of multilevel and multicomponent interventions. Makkalai Thedi Maruthuvam (MTM) is a complex multilevel, multicomponent intervention developed and implemented by the south Indian State of Tamil Nadu. The scheme aims to deliver services for preventing and controlling diabetes, and hypertension at doorstep. This paper describes the protocol for planning and conducting the process evaluation of the MTM scheme. Methods and analysis: The process evaluation uses mixed methods (secondary data analysis, key informant interviews, in-depth interviews, conceptual content analysis of documents, facility-based survey and non-participant observation) to evaluate the implementation of the MTM scheme. The broad evaluation questions addressed the fidelity, contexts, mechanisms of impact and challenges encountered by the scheme using the Consolidated Framework for Implementation Research (CFIR) framework. The specific evaluation questions addressed selected inputs and processes identified as critical to implementation by the stakeholders. The CFIR framework will guide the thematic analysis of the qualitative interviews to explore the adaptations and deviations introduced during implementation in various contexts. The quantitative data on the indicators developed for the specific evaluation questions will be cleaned and descriptively analysed.
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AZD1222 (ChAdOx1 nCoV-19) is a replication-deficient adenoviral vectored coronavirus disease-19 (COVID-19) vaccine that is manufactured as SII-ChAdOx1 nCoV-19 by the Serum Institute of India Pvt Ltd following technology transfer from Oxford University/AstraZeneca. The non-inferiority of SII-ChAdOx1 nCoV-19 with AZD1222 was previously demonstrated in an observer-blind, phase 2/3 immuno-bridging study (trial registration: CTRI/2020/08/027170). In this analysis of immunogenicity and safety data 6 months post first vaccination (Day 180), 1,601 participants were randomized 3:1 to SII-ChAdOx1 nCoV-19 or AZD1222 (immunogenicity/reactogenicity cohort n = 401) and 3:1 to SII-ChAdOx1 nCoV-19 or placebo (safety cohort n = 1,200). Immunogenicity was measured by anti-severe acute respiratory syndrome coronavirus 2 spike (anti-S) binding immunoglobulin G and neutralizing antibody (nAb) titers. A decline in anti-S titers was observed in both vaccine groups, albeit with a greater decline in SII-ChAdOx1 nCoV-19 vaccinees (geometric mean titer [GMT] ratio [95% confidence interval (CI) of SII-ChAdOx1 nCoV-19 to AZD1222]: 0.60 [0.41-0.87]). Consistent similar decreases in nAb titers were observed between vaccine groups (GMT ratio [95% CI]: 0.88 [0.44-1.73]). No cases of severe COVID-19 were reported following vaccination, while one case was observed in the placebo group. No causally related serious adverse events were reported through 180 days. No thromboembolic or autoimmune adverse events of special interest were reported. Collectively, these data illustrate that SII-ChAdOx1 nCoV-19 maintained a high level of immunogenicity 6 months post-vaccination. SII-ChAdOx1 nCoV-19 was safe and well tolerated.
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COVID-19 , ChAdOx1 nCoV-19 , Adulto , Humanos , Vacinas contra COVID-19/efeitos adversos , Seguimentos , COVID-19/prevenção & controle , Imunoglobulina G , Imunogenicidade da Vacina , Anticorpos AntiviraisRESUMO
Estimating the burden of TB at the subnational level is critical to planning and prioritizing resources for TB control activities according to the local epidemiological situation. We report the experiences and operational challenges of implementing a TB prevalence survey at the subnational level in India. Information was collected from research reports that gathered data from periodic meetings, informal discussions with study teams, letters of communication, and various site visit reports. During the implementation of the survey, several challenges were encountered, including frequent turnover in human resources, lack of survey participation and community engagement, breakdown of X-ray machines, laboratory issues that delayed sputum sample testing, delays in X-ray reading, and network and Internet connectivity issues that impeded data management. To help ensure the survey was implemented in a timely manner, we developed several solutions, including planning ahead to anticipate challenges, ensuring timely communication, having a high commitment from all stakeholders, having strong team motivation, providing repetitive hands-on training, and involving local leaders to increase community engagement. This experience may help future states and countries that plan to conduct TB prevalence surveys to address these anticipated challenges and develop alternative strategies well in advance.
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Motivação , Humanos , Prevalência , Índia/epidemiologiaRESUMO
This study employs repeated, large panels of serological surveys to document rapid and substantial waning of SARS-CoV-2 antibodies at the population level and to calculate the extent to which infection and vaccination separately contribute to seroprevalence estimates. Four rounds of serological surveys were conducted, spanning two COVID waves (October 2020 and April-May 2021), in Tamil Nadu (population 72 million) state in India. Each round included representative populations in each district of the state, totaling ≥ 20,000 persons per round. State-level seroprevalence was 31.5% in round 1 (October-November 2020), after India's first COVID wave. Seroprevalence fell to 22.9% in round 2 (April 2021), a roughly one-third decline in 6 months, consistent with dramatic waning of SARS-Cov-2 antibodies from natural infection. Seroprevalence rose to 67.1% by round 3 (June-July 2021), with infections from the Delta-variant induced second COVID wave accounting for 74% of the increase. Seroprevalence rose to 93.1% by round 4 (December 2021-January 2022), with vaccinations accounting for 63% of the increase. Antibodies also appear to wane after vaccination. Seroprevalence in urban areas was higher than in rural areas, but the gap shrunk over time (35.7 v. 25.7% in round 1, 89.8% v. 91.4% in round 4) as the epidemic spread even in low-density rural areas.
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COVID-19 , Humanos , Índia/epidemiologia , COVID-19/epidemiologia , COVID-19/prevenção & controle , SARS-CoV-2 , Estudos Soroepidemiológicos , Vacinação , Anticorpos AntiviraisAssuntos
COVID-19 , Joias , Humanos , COVID-19/epidemiologia , Índia/epidemiologia , Surtos de DoençasRESUMO
Introduction: On February 2, 2020, the head of a visually impaired school notified similar eye symptoms among the students. We investigated the cluster to confirm the diagnosis, identify potential exposures, and propose recommendations. Methodology: We defined a case as redness/watering/discharge from any eye among the students and staff, January-February 2020. We actively searched for the cases and calculated attack rates. We drew epicurve by date of symptoms onset. We conducted a retrospective cohort study of students and staff. We collected data on potential exposures and calculated Risk Ratio (RR), 95% Confidence Interval (95%CI), and Population Attributable Risk (PAR). We sent a conjunctival swab of the three cases for microbiological analysis. Results: We diagnosed the cases as acute conjunctivitis and identified 39 (76%) cases among 51 individuals. All the 39 cases reported watering and redness; 28 (72%) and 12 (31%) reported eye pain and discharge, respectively. The median age of the case was 11 years (range: 6-48 years). The attack rate didn't differ significantly between males [77% (20/26)] and females [76% (19/25), p = 0.9]. The attack rate was higher among the students [86%, (38/44)] than staffs [14%, (1/7), p = <0.01]. Contact with a case [RR = 2.5, 95%CI = 1.3-4.8, PAR = 51%] and staying inside campus [RR = 6.0, 95%CI = 1.0-37.3, PAR = 81%] were associated with the acute conjunctivitis outbreak. All the three conjunctival swabs were negative for bacterial growth. Conclusion: Close contact with the case and staying inside the campus led to the outbreak of acute conjunctivitis among the students and staff of the visually impaired school.
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Conjuntivite Viral , Conjuntivite , Adolescente , Adulto , Criança , Conjuntivite/epidemiologia , Surtos de Doenças , Feminino , Humanos , Índia/epidemiologia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Instituições Acadêmicas , Estudantes , Adulto JovemRESUMO
Background & objectives: COVID-19 cases have been rising rapidly in countries where the SARS-CoV-2 variant of concern (VOC), Omicron (B.1.1.529) has been reported. We conducted a study to describe the epidemiological and clinical characteristics and outcomes of COVID-19 patients with 'S' gene target failure (SGTF, suspected Omicron). Furthermore, their clinical outcomes with COVID-19 patients with non-SGTF (non-Omicron) were also compared. Methods: This study was conducted in Tamil Nadu, India, between December 14, 2021 and January 7, 2022 among patients who underwent reverse transcription-PCR testing for SARS-CoV-2 in four laboratories with facilities for S gene screening. Consecutively selected COVID-19 patients with SGTF were telephonically contacted, seven and 14 days respectively after their date of positive result to collect information on the socio-demographic characteristics, previous history of COVID-19, vaccination status and clinical course of illness along with treatment details. To compare their outcomes with non-SGTF patients, one randomly suspected non-Omicron case for every two suspected Omicron cases from the line-list were selected, matching for the date of sample collection and the testing laboratory. Results: A total of 1175 SGTF COVID-19 patients were enrolled for this study. Almost 6 per cent (n=72) reported a history of previous infection. 141 (13.5%) suspected Omicron cases were non-vaccinated, while 148 (14.2%) and 703 (67.4%) had received valid one and two doses of COVID-19 vaccines, respectively. Predominant symptoms reported included fever (n=508, 43.2%), body pain (n=275, 23.4%), running nose (n=261, 22.2%) and cough (n=249, 21.2%). Five (0.4%) of the 1175 suspected Omicron cases required oxygen supplementation as compared to ten (1.6%) of the 634 suspected non-Omicron cases. No deaths were reported among omicron suspects, whereas there were four deaths among suspected non-Omicron cases. Interpretation & conclusions: Majority of the suspected Omicron cases had a mild course of illness. The overall severity of these cases was less compared to the suspected non-Omicron cases.
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COVID-19 , SARS-CoV-2 , COVID-19/epidemiologia , Vacinas contra COVID-19 , Humanos , Índia/epidemiologia , SARS-CoV-2/genéticaRESUMO
COVID-19 pandemic threatened the world in terms of its rapid spread, strain on health infrastructure and many people lost their lives due to COVID. Mass Vaccination of public against Covid-19 were done with the notion that it protects against the severe form of the disease and death due to Covid-19. Covid vaccination was rolled out in Tamil Nadu from 16th January 2021 in a phased manner. This study was done using secondary data to assess the role of COVID vaccination in preventing ICU admission and death due to Covid-19 in Tamil Nadu for the period of August - December 2021. Unvaccinated individuals contributed to a higher proportion of hospitalization (60.9%) and ICU admission (65.5%) among Covid-19 infected during this period. Similarly, among patients who died due to Covid-19, 75.5% were unvaccinated. Odds of ICU admission and death among unvaccinated was 2.01 and 3.19 - times higher compared to fully vaccinated individuals infected with Covid-19. Unvaccinated Covid-19 patients had 2.73- and 1.46- times increased odds of dying and ICU admission respectively, compared to partially vaccinated. Population Attributable Risk showed that receiving at least one dose of vaccine could have reduced the mortality among Covid patients by 54% and ICU admission by 23.3%. This article emphasizes the need for vaccination against Covid-19 to reduce ICU admission and death among those infected with Covid-19.
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INTRODUCTION: The EQ-5D-5L questionnaire is a tool that is a very generic and preference-based instrument to describe the health-related quality of life. We have generated the stratified index utility value for the Tamil Nadu population and compared the utility values based on socio-demographic and clinical characteristics. METHODS: We conducted a community-based analytical cross-sectional study using telephonic interviews from November 2020 till December 2020 among individuals aged 18 years and above who were infected by the coronavirus confirmed with an RT-PCR within 30 days in Tamil Nadu State. EQ-5D-5L profile, socio-demographic and clinical characteristics of the study participants were collected and analysed. RESULTS: We interviewed 372 participants, with 57.5% were males, and their mean age was 44.5 ± 15.3 years. About 40% of participants reported as having comorbidities, such as diabetes (19.4%), hypertension (12.4%), heart disease (2.4%), kidney disease (0.8%) and others. The mean EQ-5D utility score was 0.925 ± 0.150, and the mean EQ-VAS was 90.68 ± 11.81. Overall, men had a higher utility value (0.938 ± 0.130) than women, (0.907 ± 0.170). Individuals with comorbidities, requiring longer hospitalisation were having lower utility scores than their counterparts. CONCLUSION: We report the EQ-5D-5L utility values for the COVID-19 illness. These values would help to estimate quality-adjusted life years in health economic evaluation studies.
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BACKGROUND: India has been severely affected by the ongoing COVID-19 pandemic. However, due to shortcomings in disease surveillance, the burden of mortality associated with COVID-19 remains poorly understood. We aimed to assess changes in mortality during the pandemic in Chennai, Tamil Nadu, using data on all-cause mortality within the district. METHODS: For this observational study, we analysed comprehensive death registrations in Chennai, from Jan 1, 2016, to June 30, 2021. We estimated expected mortality without the effects of the COVID-19 pandemic by fitting models to observed mortality time series during the pre-pandemic period, with stratification by age and sex. Additionally, we considered three periods of interest: the first 4 weeks of India's first lockdown (March 24 to April 20, 2020), the 4-month period including the first wave of the pandemic in Chennai (May 1 to Aug 31, 2020), and the 4-month period including the second wave of the pandemic in Chennai (March 1 to June 30, 2021). We computed the difference between observed and expected mortality from March 1, 2020, to June 30, 2021, and compared pandemic-associated mortality across socioeconomically distinct communities (measured with use of 2011 census of India data) with regression analyses. FINDINGS: Between March 1, 2020, and June 30, 2021, 87 870 deaths were registered in areas of Chennai district represented by the 2011 census, exceeding expected deaths by 25 990 (95% uncertainty interval 25 640-26 360) or 5·18 (5·11-5·25) excess deaths per 1000 people. Stratified by age, excess deaths numbered 21·02 (20·54-21·49) excess deaths per 1000 people for individuals aged 60-69 years, 39·74 (38·73-40·69) for those aged 70-79 years, and 96·90 (93·35-100·16) for those aged 80 years or older. Neighbourhoods with lower socioeconomic status had 0·7% to 2·8% increases in pandemic-associated mortality per 1 SD increase in each measure of community disadvantage, due largely to a disproportionate increase in mortality within these neighbourhoods during the second wave. Conversely, differences in excess mortality across communities were not clearly associated with socioeconomic status measures during the first wave. For each increase by 1 SD in measures of community disadvantage, neighbourhoods had 3·6% to 8·6% lower pandemic-associated mortality during the first 4 weeks of India's country-wide lockdown, before widespread SARS-CoV-2 circulation was underway in Chennai. The greatest reductions in mortality during this early lockdown period were observed among men aged 20-29 years, with 58% (54-62) fewer deaths than expected from pre-pandemic trends. INTERPRETATION: Mortality in Chennai increased substantially but heterogeneously during the COVID-19 pandemic, with the greatest burden concentrated in disadvantaged communities. Reported COVID-19 deaths greatly underestimated pandemic-associated mortality. FUNDING: National Institute of General Medical Sciences, Bill & Melinda Gates Foundation, National Science Foundation. TRANSLATION: For the Hindi translation of the abstract see Supplementary Materials section.
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COVID-19 , Pandemias , Adulto , Idoso , Idoso de 80 Anos ou mais , Controle de Doenças Transmissíveis , Humanos , Índia/epidemiologia , Masculino , Pessoa de Meia-Idade , Mortalidade , SARS-CoV-2 , Adulto JovemAssuntos
Gastroenterite , Oryza , Humanos , Índia/epidemiologia , Férias e Feriados , Gastroenterite/epidemiologia , Surtos de DoençasRESUMO
Background: A screening program for cervical cancer was established in 2011 in Tamil Nadu. Since the inception of the program, coverage, and dropout of screening has not been analyzed. We conducted a study to describe the referral mechanism in the cervical cancer screening program implemented in Tamil Nadu, to estimate the level of adherence to the referral process by the beneficiaries, and to identify strengths and weaknesses related to the referral mechanism in the program. Methods: ">This descriptive study was conducted during 2015-2016 in the Tiruchirappalli administrative district of Tamil Nadu. All women aged 30 years and above, who were screened in public health facilities, were the participants. Using a structured form, we collected the data maintained in the registers at the district health administration. We estimated the screening coverage, follow-up evaluation, and dropout rates at different stages of the referral mechanism. We used SPSS and Epi Info software for analysis. Results: Coverage of cervical cancer screening was 4,838(41.6%). We estimated 4,838(41.6%) of screened positives were lost to follow-up for a colposcopy examination. Biopsy samples were obtained from 3425(84%) of those who required a biopsy. Cervical cancer was diagnosed in 159(4.6%) and precancerous lesions in 528(15.4%) women. Conclusion: More than half of the target population was screened in public health facilities. The dropout rate was less than half of those screened at the colposcopy evaluation level. Major pitfalls of the program were human resource issues at referral centers and poor maintenance of meaningful data.
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Neoplasias do Colo do Útero , Colposcopia , Detecção Precoce de Câncer , Feminino , Humanos , Índia/epidemiologia , Masculino , Programas de Rastreamento , Gravidez , Encaminhamento e Consulta , Neoplasias do Colo do Útero/diagnóstico , Neoplasias do Colo do Útero/epidemiologia , Neoplasias do Colo do Útero/patologiaRESUMO
BACKGROUND: Lack of effective early screening is a major obstacle for reducing the fatality rate and disease burden of dengue. In light of this, the government of Tamil Nadu has adopted a decentralized dengue screening strategy at the primary healthcare (PHC) facilities using blood platelet count. Our objective was to determine the cost-effectiveness of a decentralized screening strategy for dengue at PHC facilities compared with the current strategy at the tertiary health facility (THC) level. METHODS: Decision tree analysis followed a hypothetical cohort of 1000 suspected dengue cases entering the model. The cost-effectiveness analysis was performed at a 3% discount rate for the proposed and current strategy. The outcomes are expressed in incremental cost-effectiveness ratios (ICERs) per quality-adjusted life years gained. One-way sensitivity analysis and probabilistic sensitivity analysis were done to check the uncertainty in the outcome. RESULTS: The proposed strategy was found to be cost-saving and ICER was estimated to be -41 197. PSA showed that the proposed strategy had a 0.84 probability of being an economically dominant strategy. CONCLUSIONS: The proposed strategy is cost-saving, however, it is recommended to consider optimal population coverage, costs to economic human resources and collateral benefits of equipment.
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Dengue , Doenças Transmitidas por Vetores , Análise Custo-Benefício , Dengue/diagnóstico , Dengue/prevenção & controle , Humanos , Índia , Anos de Vida Ajustados por Qualidade de VidaRESUMO
BACKGROUND: This phase 2/3 immunobridging study evaluated the safety and immunogenicity of the ChAdOx1 nCoV-19 Coronavirus Vaccine (Recombinant) (SII-ChAdOx1 nCoV-19), manufactured in India at the Serum Institute of India Pvt Ltd (SIIPL), following technology transfer from the AstraZeneca. METHODS: This participant-blind, observer-blind study randomised participants 3:1 to SII-ChAdOx1 nCoV-19 or AZD1222 (ChAdOx1 nCoV-19) (immunogenicity/reactogenicity cohort) and 3:1 to SII-ChAdOx1 nCoV-19 or placebo (safety cohort). The study participants were enrolled from 14 hospitals across India between August 25 and October 31, 2020. Two doses of study products were given 4 weeks apart. The primary objectives were to demonstrate non-inferiority of SII-ChAdOx1 nCoV-19 to AZD1222 in terms of geometric mean titre (GMT) ratio of anti-SARS-CoV-2 spike IgG antibodies 28 days after the second dose (defined as lower limit of 95% CI >0·67) and to determine the incidence of serious adverse events (SAEs) causally related to SII-ChAdOx1 nCoV-19. The anti-spike IgG response was assessed using a multiplexed electrochemiluminescence-based immunoassay. Safety follow-up continued until 6 months after first dose. Trial registration: CTRI/2020/08/027170. FINDINGS: 1601 participants were enrolled: 401 to the immunogenicity/reactogenicity cohort and 1200 to the safety cohort. After two doses, seroconversion rates for anti-spike IgG antibodies were more than 98·0% in both the groups. SII-ChAdOx1 nCoV-19 was non-inferior to AZD1222 (GMT ratio 0·98; 95% CI 0·78-1·23). SAEs were reported in ≤ 2·0% participants across the three groups; none were causally related. A total of 34 SARS-CoV-2 infections were reported; of which 6 occurred more than 2 weeks after the second dose; none were severe. INTERPRETATION: SII-ChAdOx1 nCoV-19 has a non-inferior immune response compared to AZD1222 and an acceptable safety/reactogenicity profile. Pharmacovigilance should be maintained to detect any safety signals. FUNDING: SIIPL funded the contract research organisation and laboratory costs, while the site costs were funded by the Indian Council of Medical Research. The study vaccines were supplied by SIIPL and AstraZeneca.