Harmonization of Zika serological assays and comparative evaluation of two commercial ZIKA IgG ELISA kits.

The interpretation for Zika virus serology results is challenging due to high antibody cross reactivity with other flaviviruses. This limits availability of reliable and accurate methods for serosurveillance studies to understand the disease burden. Therefore, we conducted study to harmonize anti-Zika IgG antibody detection assays with 1st WHO International Standard (16/352) and working standard (16/320) for anti-Zika virus antibody.Additionally, evaluated NuGenTMZIKA-IgG and NovaLisa®ZIKA virus IgG-Capture ELISA using a panel of 278 seraFurther, 106 samples positive for other-flavi viruses were taken for assessing cross-reactivity of the assay, all serums were further tested by Zika-PRNT. The results of this study indicates satisfactory performance of both the assays. Serological and neutralization assays were calibrated according to the international standards. This will help in understanding antibody dynamics in serosurveillance and vaccine studies. However the performance of the kits with possibilities of cross-reactivity will have to be verified by coupling ZIKV and DENV specific ELISA.

Seroprevalence of dengue virus infection in Pune City in India, 2019: A decadal change.

BACKGROUND: The burden of dengue infection needs to be monitored along with tracking of the changes in dengue virus (DENV) transmission intensity for vaccine introduction decisions. METHODS: The seroprevalence of dengue was investigated in Pune City in India, in early 2019 using 1654 sera from apparently healthy human participants enrolled randomly through multistage cluster sampling. We used 797 retrospective human sera from late 2009 for comparison. All sera were assessed for the presence of dengue-specific IgG antibodies. A subset (n = 230) was tested for serotype-specific plaque reduction-neutralizing antibodies against all four serotypes. RESULTS: The dengue IgG seroprevalence of 62.9% (95% CI 59.4-66.1) in 2009 increased to 88.4% (95% CI 86.8-89.8) in 2019. Age-stratified dengue seroprevalence revealed a gradual increase in IgG seropositivity from 70.1% in 0-9 years to 85.0% in 10-19 years. The annual probability of dengue infection estimated as a force of infection was 4.1 (95% CI 3.8-4.5) in 2009, which increased to 10.9 (95% CI 10.2-11.6) in 2019. Analysis of dengue serotype-specific neutralizing antibodies revealed DENV-3 as the dominant serotype. The age of exposure to at least one dengue serotype was reduced in 2019 over 2009. CONCLUSIONS: There was a significant increase in the intensity of dengue virus transmission in Pune City over the decade. Since over 85% of the participants above nine years of age had exposure to DENV by 2019, dengue vaccine introduction can be considered. Moreover, such repeated serosurveys in different regions might inform about the readiness of the population for dengue vaccination.

A scoping review of persistent symptoms after COVID infection at different follow-up periods.

The clinical entity termed as long COVID has gained importance in the recent past. As this phenomenon is still evolving, it is important to document the magnitude of the syndrome during different time periods. This scoping review attempts to synthesize evidence generated from longitudinal studies which have follow-up periods beyond 3 months, up to 12 months. The review also documents the reported prevalence of long COVID for the different regions of the World Health Organization. Longitudinal studies published till March 2022 were systematically searched on PubMed, Google Scholar, and medRxiv. Among the identified 594 studies, 48 were included in this review. Data from selected studies were synthesized. The overall pooled prevalence of long COVID was 49% (40%-58%). The pooled estimates after 3 months, 4-6 months, 7-9 months, and 10-12 months were 44% (32%-57%), 50% (43%-57%), 49% (37%-62%), and 54% (46%-62%), respectively. Eastern Mediterranean Region (EMR) had the highest pooled prevalence of 63% (34%-92%] and the South East Asian Region (SEAR) had the least pooled estimate of 15% (10%-21%). The study brings out the high prevalence of long COVID even after 12 months of follow-up. It also shows the regional differences in the reported prevalence of the syndrome. This review highlights the need for well-planned follow-up studies, especially in developing nations to understand the magnitude and the pattern of long COVID-related symptoms as they emerge.

Infectious Causes of Acute Encephalitis Syndrome in India - Decadal Change and the Way Forward.

The diagnosis and management of encephalitis were previously largely based on clinical grounds and minimal laboratory investigations. Japanese encephalitis (JE) gets considered as the probable diagnosis in most encephalitis cases. However, reports of JE in adults and the elderly are increasing after the JE vaccine introduction among children in 2006. The Nipah virus (NiV) emerged in 2002 and continues to afflict humans in new geographic areas. Many other infections cause encephalitis, including Chandipura, chikungunya, dengue, and West Nile. Significant advances in diagnostic testing like multiplex testing panels and metagenomic approaches along with sequencing have helped in the detection of new etiologies. Recent years have witnessed an increase in climate-sensitive zoonotic diseases with encephalitis. This highlights the importance of the One Health approach in studying the impact of climate change-associated infectious diseases on human health. The government of India's efforts to develop health research infrastructure would help future responses to emerging infectious disease epidemics.

Incidence of Japanese Encephalitis and Acute Encephalitis Syndrome Hospitalizations in the Medium-Endemic Region in Central India.

BACKGROUND: We estimated the incidence of Japanese encephalitis (JE) and acute encephalitis syndrome (AES) following routine immunization with the live-attenuated SA 14-14-2 JE vaccine. METHODS: We implemented enhanced surveillance of AES and JE hospitalizations in endemic districts in Maharashtra and Telangana States during 2015-2016 and 2018-2020. We estimated incidence and compared differences in the incidence of JE and AES between two states, and vaccinated and unvaccinated districts during two study periods. We also considered secondary data from public health services to understand long-term trends from 2007 to 2020. RESULTS: The annual AES incidence rate of 2.25 cases per 100,000 children in Maharashtra during 2018-2020 was significantly lower than 3.36 cases per 100,000 children during 2015-2016. The six JE-vaccinated districts in Maharashtra had significantly lower incidence rates during 2018-2020 (2.03, 95% CI 1.73-2.37) than in 2015-16 (3.26, 2.86-3.70). In addition, the incidence of both JE and AES in two unvaccinated districts was higher than in the vaccinated districts in Maharashtra. Telangana had a lower incidence of both JE and AES than Maharashtra. The AES incidence rate of 0.95 (0.77-1.17) during 2018-2020 in Telangana was significantly lower than 1.67 (1.41-1.97) during 2015-2016. CONCLUSIONS: The annual incidence rate of Japanese encephalitis was < 1 case per 100,000 children. It indicated accelerated control of Japanese encephalitis after routine immunization. However, the annual incidence of acute encephalitis syndrome was still > 1 case per 100,000 children. It highlights the need for improving surveillance and evaluating the impacts of vaccination.

Effectiveness of Japanese encephalitis vaccination among children in central India.

Japanese encephalitis (JE) disease among children continues in central India despite vaccination implemented in the routine immunization program. Therefore, we planned to estimate the JE vaccination effectiveness among children by undertaking a 1:2 individually-matched population-based case-control study from August 2018 to October 2020. The laboratory-confirmed JE cases aged 1-15 years were enrolled along with neighborhood controls without fever and encephalitis matched on the residence area, age and sex. The JE vaccination history was enquired from parents and verified independently from the vaccination cards available at home and records at health facilities. We enrolled 35 JE cases and 70 matched controls. The vaccination effectiveness of 86.7% (95% confidence interval [CI]: 30.8-94.7) was estimated on the per-protocol analysis of 31 case-control sets. The screening method provided an effectiveness of 89.5% (CI: 78.9-94.7) on using the population vaccination coverage of 90% reported earlier in the same area. In conclusion, JE vaccination offered a moderate level of protection among children in JE medium-endemic central India, similar to reports from high-endemic areas in India. The operational aspects of vaccination program implementation need to be evaluated to assess the impact of vaccination on the disease burden of JE in medium-endemic regions of India.

Evaluating the effect of measles and rubella mass vaccination campaigns on seroprevalence in India: a before-and-after cross-sectional household serosurvey in four districts, 2018-2020.

BACKGROUND: India did phased measles-rubella supplementary immunisation activities (MR-SIAs; ie, mass-immunisation campaigns) targeting children aged 9 months to less than 15 years. We estimated measles-rubella seroprevalence before and after the MR-SIAs to quantify the effect on population immunity and identify remaining immunity gaps. METHODS: Between March 9, 2018 and March 19, 2020 we did community-based, cross-sectional serosurveys in four districts in India before and after MR-SIAs. 30 villages or wards were selected within each district, and one census enumeration block from each was selected as the survey cluster. Households were enumerated and 13 children in the younger age group (9 months to <5 years) and 13 children in the older ager group (5 to <15 years) were randomly selected by use of computer-generated random numbers. Serum samples were tested for IgG antibodies to measles and rubella viruses by enzyme immunoassay. FINDINGS: Specimens were collected from 2570 children before the MR-SIA and from 2619 children afterwards. The weighted MR-SIA coverage ranged from 73·7% to 90·5% in younger children and from 73·6% to 93·6% in older children. Before the MR-SIA, district-level measles seroprevalence was between 80·7% and 88·5% among younger children in all districts, and between 63·4% and 84·5% among older children. After the MR-SIA, measles seroprevalence among younger children increased to more than 90% (range 91·5 to 96·0) in all districts except Kanpur Nagar, in which it remained unchanged 80·4%. Among older children, measles seroprevalence increased to more than 90·0% (range 93·7% to 96·5%) in all districts except Hoshiarpur (88·7%). A significant increase in rubella seroprevalence was observed in all districts in both age groups, with the largest effect in Dibrugarh, where rubella seroprevalence increased from 10·6% to 96·5% among younger children. INTERPRETATION: Measles-rubella seroprevalence increased substantially after the MR-SIAs but the serosurvey also identified remaining gaps in population immunity. FUNDING: The Bill & Melinda Gates Foundation and Indian Council of Medical Research.

A simple scheme for large scale purification of urine - Derived Bence Jones Kappa protein.

We have investigated and optimized purification process, suitable for industrial scale, to obtain high purity grade Bence Jones Kappa Protein ('BJK-Protein'), while preserving its physiological properties and functions. BJK-Protein was obtained from a biological waste product i.e. human urine of renal failure patients. Isolated 'BJK-Protein' was analyzed by electrophoresis, western blotting, double immunodiffusion, SEC-HPLC assay and Mass Spectrometry (MS). The relative molecular mass of 'BJK-Protein' is 23054.2 Da. Moreover, dimer forms of 'BJK-Protein' were also detected in SDS-PAGE and mass spectrum corresponding to 46054.4 Da. The results of western blotting, immunoelectrophoresis, SEC-HPLC assay, and mass spectrometry analysis indicate a high purity (>99 %) of 'BJK-Protein'. Peptide mass fingerprint analysis of 'BJK-Protein' yielded peptides that partially matches the known database sequences of kappa variable region (KV139_HUMAN) of immunoglobulin. This protein was found to be stable up to 20 months at 2-8 °C temperature and also found negative for major undesirable viral markers as well as bacterial endotoxin. With this purification approach, the cost of purified 'BJK-Protein' is significantly reduced as compared to the current market price of Kappa light chain available in international market.

Coverage of Japanese encephalitis routine vaccination among children in Central India.

BACKGROUND: We aimed to estimate the coverage of Japanese encephalitis (JE) vaccination in central India to help explain the continued occurrence of JE disease despite routine vaccination. METHODS: We implemented a 30-cluster survey for estimating the coverage of JE vaccination in the medium-endemic areas implemented with JE vaccination in central India. The parents were enquired about the uptake of the JE vaccine by their children aged 2 to 6 years, followed by verification of the immunization cards at home along with reasons for non-vaccination. Vaccination coverage was reported as a percentage with 95% confidence intervals. RESULTS: We estimated high coverage of live-attenuated SA 14-14-2 JE vaccination in Maharashtra (94.8%, 95% CI 92.7-96.3) and Telangana (92.8%, 90.0-94.9). The vaccination card retention was 90.3% in Maharashtra and 70.4% in Telangana state. There were no gender differences in coverage in both states. A similar level of JE vaccination coverage was observed during the year 2013 to 2021 in both states. In Maharashtra, the maximum age-wise coverage was 96.6% in the >60 months age category, whereas in Telangana it was in the <24 months age category (97.2%). The timeliness of JE vaccination was appropriate and similar in both states. We found very good agreement between JE and Measles-Rubella vaccinations administered simultaneously. The reasons for non-vaccination were the shortage of vaccines and the parental migration for work. CONCLUSIONS: The coverage of Japanese encephalitis vaccination was high in medium-endemic regions in central India. Vaccination effectiveness studies may help further explain the continued incidence of Japanese encephalitis. This article is protected by copyright. All rights reserved.

Infectious causes of acute encephalitis syndrome hospitalizations in Central India, 2018-20.

BACKGROUND: We enhanced surveillance of hospitalizations of all ages for acute encephalitis syndrome (AES) along with infectious aetiologies, including the Japanese encephalitis virus (JEV). METHODS: From October 2018 to September 2020, we screened neurological patients for AES in all age groups in Maharashtra and Telangana States. AES cases were enrolled at study hospitals along with other referrals and sampled with cerebrospinal fluid, acute and convalescent sera. We tested specimens for non-viral aetiologies viz. leptospirosis, typhoid, scrub typhus, malaria and acute bacterial meningitis, along with viruses - JEV, Dengue virus (DENV), Chikungunya virus (CHIKV), Chandipura virus (CHPV) and Herpes simplex virus (HSV). RESULTS: Among 4977 neurological hospitalizations at three study site hospitals over two years period, 857 (17.2%) were AES. However, only 287 (33.5%) AES cases were eligible. Among 278 (96.9%) enrolled AES cases, infectious aetiologies were identified in 115 (41.4%) cases, including non-viral in 17 (6.1%) cases - leptospirosis (8), scrub-typhus (3) and typhoid (6); and viral in 98 (35.3%) cases - JEV (58, 20.9%), HSV (22, 7.9%), DENV (15, 5.4%) and CHPV (3, 1.1%). JEV confirmation was significantly higher in enrolled cases than referred cases (10.2%) (p < 0.05). However, the contribution of JEV in AES cases was similar in both children and adults. JE was reported year-round and from adjacent non-endemic districts. CONCLUSIONS: The Japanese encephalitis virus continues to be the leading cause of acute encephalitis syndrome in central India despite vaccination among children. Surveillance needs to be strengthened along with advanced diagnostic testing for assessing the impact of vaccination.

Epidemiological findings for the first and second waves of COVID-19 pandemic in Maharashtra, India.

India is one of the worst affected countries during the COVID-19 pandemic. We carried out comparative analyses of the COVID-19 situation in the Maharashtra state, India for the first and second waves. Epidemiological and demographics data were obtained from open sources and the Government of Maharashtra. Mathematical modeling and analyses were conducted to estimate the epidemiological parameters like basic reproduction number (R0) for the first wave at different times. The districts with a higher percentage of the urban population recorded a higher attack rate during the first wave. However, during the second wave, the rural population was more affected. The effective reproduction number (Re) was estimated for the second wave at different times. The second wave affected more individuals than the first wave due to various factors such as strictness of restrictions or the lack of it and the emergence of new strains.

Seroprevalence of SARS-CoV-2 infection among frontline police personnel in Mumbai, India.

Introduction: A serosurvey was designed to ascertain the extent of infection among police personnel in Mumbai, India, during the last week of January 2021, at the end of the first wave of the COVID-19 pandemic, and just before the introduction of vaccination. Methods: The survey was carried out to screen for SARS-CoV-2 among 3232 police personnel. Of the 3176 participants willing for blood sample collection, 3077 personnel were found to be eligible for testing antibodies against the SARS-CoV-2 virus using the Roche Diagnostics' Elecsys Anti-SARS-CoV-2 assay. Results: The overall seroprevalence was 74.1% (95% CI 72.5-75.6). Males (75.1%, 73.4-76.8) had significantly higher seroprevalence than females (69.8%, 66.0-73.3), 18-39 years age group (76.4%, 74.4-78.3) than 40-59 years age group (70.6%, 67.9-73.1), non-officers (75.2%, 73.5-76.7) than officers (63.8%, 58.2-69.0), and personnel without comorbidities (75.0%, 73.3-76.6) than with comorbidities (69.7%, 65.6-73.5). Additionally, personnel with resident members positive for COVID-19 (89.6%, 84.7-93.1), personnel having reported COVID-19 earlier (95.5%, 93.8-96.7), and personnel having PCR positivity earlier (96.4%, 94.7-97.6) had significantly higher seroprevalences than others. All other variables, including diabetes and blood glucose status, lipid levels and thyroid enzymes, were not significantly associated with the seroprevalence levels. Conclusions: Almost three-fourths of frontline police personnel had evidence of past COVID-19 infection at the end of the first wave in January 2021, just before the introduction of COVID-19 vaccination. These frontline non-healthcare essential workers are an important risk group, and amenable to rapid serosurveys. These findings may help in estimating transmission status in the general community, along with disease burden, aiding prioritization of healthcare services.

Decadal Change in Seroprevalence of Chikungunya Virus Infection in Pune City, India.

Chikungunya virus (CHIKV) is an arthropod-borne virus capable of causing large outbreaks. We aimed to determine the decadal change in the extent of chikungunya virus infection from 2009 to 2019. We implemented a prospective cross-sectional survey in Pune City using a 30-cluster approach with probability-proportion-to-size (PPS) sampling, with blood samples collected from 1654 participants in early 2019. The study also included an additional 799 blood samples from an earlier serosurvey in late 2009. The samples were tested by an in-house anti-CHIKV IgG ELISA assay. The overall seroprevalence in 2019 was 53.2% (95% CI 50.7−55.6) as against 8.5% (95% CI 6.5−10.4) in 2009. A fivefold increase in seroprevalence was observed in a decade (p < 0.00001). The seroprevalence increased significantly with age; however, it did not differ between genders. Modeling of age-stratified seroprevalence data from 2019 coincided with a recent outbreak in 2016 followed by the low-level circulation. The mean estimated force of infection during the outbreak was 35.8% (95% CI 2.9−41.2), and it was 1.2% after the outbreak. To conclude, the study reports a fivefold increase in the seroprevalence of chikungunya infection over a decade in Pune City. The modeling approach considering intermittent outbreaks with continuous low-level circulation was a better fit and coincided with a recent outbreak reported in 2016. Community engagement and effective vector control measures are needed to avert future chikungunya outbreaks.

Enablers and barriers towards ensuring routine immunization services during the COVID-19 pandemic: findings from a qualitative study across five different states in India.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has led to disruption in delivering routine healthcare services including routine immunization (RI) worldwide. Understanding the enablers and barriers for RI services during a pandemic is critically important to develop context-appropriate strategies to ensure uninterrupted routine services. METHODS: A community-based, cross-sectional descriptive study was conducted in five different states of India, nested within an ongoing multicentric study on RI. Telephone in-depth interviews among 56 health workers were carried out and the data were analyzed using a content analysis method. RESULTS: During the COVID-19 pandemic, healthcare providers encountered many challenges at the health system, community and individual level when rendering RI services. Challenges like the limited availability of personal protective equipment and vaccines, deployment for COVID-19 duty at system level, the difficulty in mobilizing people in the community, fear among people at community level, mobility restrictions and limited family support, as well as the stress and stigma at individual level, were barriers to providing RI services. By contrast, the issuing of identification cards to health staff, engaging community volunteers, the support given to health workers by their families and training on COVID-19, were factors that enabled health workers to maintain RI services during the pandemic. CONCLUSIONS: When addressing the COVID-19-related public health emergency, we should not lose sight of the importance of services like RI.

Outbreak of cholera in a remote village in western India.

Background & objectives: Atypical El Tor strains of Vibrio cholerae are frequently implicated in outbreaks of cholera. It is important to understand genetic variations of such strains which impact clinical and epidemiological outcomes. The present study was carried out to characterize an outbreak of cholera which occurred between July 8 and 13, 2018, in a remote settlement in Nashik district, Maharashtra. Methods: A large number of acute diarrhoea cases were reported in Rahude village, Nashik, Maharashtra since July 8, 2018. Molecular characterization of the isolated strains of V. cholerae was done. Results: 195 cases of cholera were detected from a population of 850 (attack rate 22.9%) with two deaths (Case Fatality Ratio of 1.03). A non-haemolytic polymyxin B sensitive strain of V. cholerae O1 Ogawa was isolated from 5/14 fecal samples. Molecular characterization of the isolates indicated that this strain was an altered El Tor (AET) strain. Deletion of the trinucleotide 'GTA' in the rstB gene, a unique feature of classical strains, was observed. Interpretation & conclusions: A cholera outbreak caused by a non-haemolytic polymixin B sensitive AET strain, occurred from July 8 to 13, 2018, in a remote settlement in western India. The molecular characterization of the outbreak strains highlighted an assortment of genetic determinants, stressing the need to monitor the genetic attributes of V. cholerae O1 in outbreaks for better understanding and mapping of clinical and epidemiological changes.

Childhood encephalitis hospitalizations associated with virus agents in medium-endemic states in India.

BACKGROUND: Japanese encephalitis (JE) is the leading cause of childhood acute encephalitis syndrome (AES) in India. We enhanced the AES surveillance in sentinel hospitals to determine trends and virus etiologies in central India. METHODS: The neurological hospitalizations among children ≤15 years were tracked by using the AES case definition implemented by the national program. Acute and convalescent sera along with cerebrospinal fluid (CSF) specimens were collected and tested at the strengthened site hospital laboratories for anti-JE, anti-Dengue and anti-Chikungunya virus by IgM ELISA; along with Chandipura virus RT-PCR. Herpes simplex and enterovirus testing was undertaken at the reference laboratory. RESULTS: Among 1619 pediatric neurological hospitalizations reported during 2015-16, AES case definition was fulfilled in 332 (20.5%) cases. After excluding 52 non-AES cases, 280 AES cases resident from study districts were considered eligible for study. The treating physicians diagnosed non-viral causes in 90 cases, therefore 190 (67.9%) of 280 AES cases were suspected with viral etiologies. We enrolled 140 (73.7%) of 190 eligible AES cases. Viral etiologies were confirmed in 31 (22.1%) of 140 enrolled AES cases. JE (n = 22) was the leading cause. Additional non-JE viral agents included Chikungunya (5), Dengue (2) and Chandipura (2). However, only 21 (9.4%) of 222 additional AES cases referred from peripheral hospitals were confirmed as JE. CONCLUSIONS: Japanese encephalitis virus continues to be the leading cause of childhood acute encephalitis syndrome in central India despite vaccination program. Surveillance needs to be intensified for assessing the true disease burden of Japanese encephalitis following vaccination program implementation.

Seroprevalence of Dengue Infection Using IgG Capture ELISA in India, 2017-2018.

We conducted a nationally representative population-based survey in 60 districts from 15 Indian states covering all five geographic regions during 2017-2018 to estimate the age specific seroprevalence of dengue. Of the 12,300 sera collected, 4,955 were positive for IgG antibodies against dengue virus using IgG Indirect ELISA indicating past dengue infection. We tested 4,948 sera (seven had inadequate volume) positive for IgG antibodies on indirect ELISA using anti-dengue IgG capture ELISA to estimate the proportion of dengue infections with high antibody titers, suggestive of acute or recent secondary infection. Of the 4,948 sera tested, 529 (10.7%; 95% CI: 9.4-12.1) were seropositive on IgG capture ELISA. The proportions of dengue infections with high titers were 1.1% in the northeastern, 1.5% in the eastern, 6.2% in the western, 12.2% in the southern, and 16.7% in the northern region. The distribution of dengue infections varied across geographic regions, with a higher proportion of infections with high antibody titer in the northern and southern regions of India. The study findings could be useful for planning facilities for clinical management of dengue infections.

Immunity against diphtheria among children aged 5-17 years in India, 2017-18: a cross-sectional, population-based serosurvey.

BACKGROUND: Diphtheria is re-emerging as a public health problem in several Indian states. Most diphtheria cases are among children older than 5 years. In this study, we aimed to estimate age-specific immunity against diphtheria in children aged 5-17 years in India. METHODS: We used residual serum samples from a cross-sectional, population-based serosurvey for dengue infection done between June 19, 2017, and April 12, 2018, to estimate the age-group-specific seroprevalence of antibodies to diphtheria in children aged 5-17 years in India. 8309 serum samples collected from 240 clusters (122 urban and 118 rural) in 60 selected districts of 15 Indian states spread across all five geographical regions (north, northeast, east, west, and south) of India were tested for the presence of IgG antibodies against diphtheria toxoid using an ELISA. We considered children with antibody concentrations of 0·1 IU/mL or greater as immune, those with levels less than 0·01 IU/mL as non-immune (and hence susceptible to diphtheria), and those with levels in the range of 0·01 to less than 0·1 IU/mL as partially immune. We calculated the weighted proportion of children who were immune, partially immune, and non-immune, with 95% CIs, for each geographical region by age group, sex, and area of residence (urban vs rural). FINDINGS: 29·7% (95% CI 26·3-33·4) of 8309 children aged 5-17 years were immune to diphtheria, 10·5% (8·6-12·8) were non-immune, and 59·8% (56·3-63·1) were partially immune. The proportion of children aged 5-17 years who were non-immune to diphtheria ranged from 6·0% (4·2-8·3) in the south to 16·8% (11·2-24·4) in the northeast. Overall, 9·9% (7·7-12·5) of children residing in rural areas and 13·1% (10·2-16·6) residing in urban areas were non-immune to diphtheria. A higher proportion of girls than boys were non-immune to diphtheria in the northern (17·7% [12·6-24·2] vs 7·1% [4·1-11·9]; p=0·0007) and northeastern regions (20·0% [12·9-29·8] vs 12·9% [8·6-19·0]; p=0·0035). INTERPRETATION: The findings of our serosurvey indicate that a substantial proportion of children aged 5-17 years were non-immune or partially immune to diphtheria. Transmission of diphtheria is likely to continue in India until the immunity gap is bridged through adequate coverage of primary and booster doses of diphtheria vaccine. FUNDING: Indian Council of Medical Research.

Seroprevalence of chikungunya virus infection in India, 2017: a cross-sectional population-based serosurvey.

BACKGROUND: Since its re-emergence in 2005, chikungunya virus (CHIKV) transmission has been documented in most Indian states. Information is scarce regarding the seroprevalence of CHIKV in India. We aimed to estimate the age-specific seroprevalence, force of infection (FOI), and proportion of the population susceptible to CHIKV infection. METHODS: We did a nationally representative, cross-sectional serosurvey, in which we randomly selected individuals in three age groups (5-8, 9-17, and 18-45 years), covering 240 clusters from 60 selected districts of 15 Indian states spread across all five geographical regions of India (north, northeast, east, south, and west). Age was the only inclusion criterion. We tested serum samples for IgG antibodies against CHIKV. We estimated the weighted age-group-specific seroprevalence of CHIKV infection for each region using the design weight (ie, the inverse of the overall probability of selection of state, district, village or ward, census enumeration block, and individual), adjusting for non-response. We constructed catalytic models to estimate the FOI and the proportion of the population susceptible to CHIKV in each region. FINDINGS: From June 19, 2017, to April 12, 2018, we enumerated 117 675 individuals, of whom 77 640 were in the age group of 5-45 years. Of 17 930 randomly selected individuals, 12 300 individuals participated and their samples were used for estimation of CHIKV seroprevalence. The overall prevalence of IgG antibodies against CHIKV in the study population was 18·1% (95% CI 14·2-22·6). The overall seroprevalence was 9·2% (5·4-15·1) among individuals aged 5-8 years, 14·0% (8·8-21·4) among individuals aged 9-17 years, and 21·6% (15·9-28·5) among individuals aged 18-45 years. The seroprevalence was lowest in the northeast region (0·3% [95% CI 0·1-0·8]) and highest in the southern region (43·1% [34·3-52·3]). There was a significant difference in seroprevalence between rural (11·5% [8·8-15·0]) and urban (40·2% [31·7-49·3]) areas (p<0·0001). The seroprevalence did not differ by sex (male 18·8% [95% CI 15·2-23·0] vs female 17·6% [13·2-23·1]; p=0·50). Heterogeneous FOI models suggested that the FOI was higher during 2003-07 in the southern and western region and 2013-17 in the northern region. FOI was lowest in the eastern and northeastern regions. The estimated proportion of the population susceptible to CHIKV in 2017 was lowest in the southern region (56·3%) and highest in the northeastern region (98·0%). INTERPRETATION: CHIKV transmission was higher in the southern, western, and northern regions of India than in the eastern and northeastern regions. However, a higher proportion of the population susceptible to CHIKV in the eastern and northeastern regions suggests a susceptibility of these regions to outbreaks in the future. Our survey findings will be useful in identifying appropriate target age groups and sites for setting up surveillance and for future CHIKV vaccine trials. FUNDING: Indian Council of Medical Research.

An improved protocol for large scale production of high purity 'Fc' fragment of human immunoglobulin G (IgG-Fc).

We describe a simplified approach for purification and characterization of human 'IgG-Fc' fragment used widely as immunochemical tool and for therapeutic purposes. The 'Fc' fragment was purified from human IgG in a 3-stage column chromatography. The purified 'Fc' fragment appeared as a dimer glycoprotein with an apparent molecular mass of 52,981 Dalton (Ultraflex MALDI TOF/TOF). The Size-exclusion HPLC profile of the purified 'Fc' fragment of human IgG matched that of a commercially procured reference 'Fc' fragment material. The purity of the 'Fc' fragments was >99% by SDS-PAGE and size-exclusion HPLC. The results of Western blotting, immunoelectrophoresis, and mass spectrometry analysis indicate a high purity of the 'Fc' fragment. Peptide mass fingerprint analysis of the purified 'Fc' protein yielded peptides that partially match the known database sequences of FCG3B_HUMAN (Uniprot ID: O75015). This method of purification of the 'Fc' fragment is suitable for achieving high purity level of 'Fc' fragment protein. With this purification approach, the cost of the purified 'Fc' fragment of human IgG is significantly reduced as compared with the current market price of IgG-Fc fragment protein in international market. The purified 'IgG-Fc' fragment protein was found to be negative for major viral markers.