Effectiveness of an inactivated virus-based SARS-CoV-2 vaccine, BBV152, in India: a test-negative, case-control study.

BACKGROUND: BBV152 is a whole-virion inactivated SARS-CoV-2 vaccine that has been deployed in India. The results of the phase 3 trial have shown clinical efficacy of BBV152. We aimed to evaluate the effectiveness of BBV152 against symptomatic RT-PCR-confirmed SARS-CoV-2 infection. METHODS: We conducted a test-negative, case-control study among employees of the All India Institute of Medical Sciences (a tertiary care hospital in New Delhi, India), who had symptoms suggestive of COVID-19 and had an RT-PCR test for SARS-CoV-2 during the peak of the second wave of the COVID-19 pandemic in India between April 15 and May 15, 2021. Cases (test-positives) and controls (test-negatives) were matched (1:1) on the basis of age and gender. The odds of vaccination with BBV152 were compared between cases and controls and adjusted for level of occupational exposure (to COVID-19), previous SARS-CoV-2 infection, and calendar time, using conditional logistic regression. The primary outcome was effectiveness of two doses of BBV152 (with the second dose received at least 14 days before testing) in reducing the odds of symptomatic RT-PCR-confirmed SARS-CoV-2 infection, expressed as (1 - odds ratio) × 100%. FINDINGS: Between April 15 and May 15, 2021, 3732 individuals had an RT-PCR test. Of these, 2714 symptomatic employees had data on vaccination status, and 1068 matched case-control pairs were available for analysis. The adjusted effectiveness of BBV152 against symptomatic COVID-19 after two doses administered at least 14 days before testing was 50% (95% CI 33-62; p<0·0001). The adjusted effectiveness of two doses administered at least 28 days before testing was 46% (95% CI 22-62) and administered at least 42 days before testing was 57% (21-76). After excluding participants with previous SARS-CoV-2 infections, the adjusted effectiveness of two doses administered at least 14 days before testing was 47% (95% CI 29-61). INTERPRETATION: This study shows the effectiveness of two doses of BBV152 against symptomatic COVID-19 in the context of a huge surge in cases, presumably dominated by the potentially immune-evasive delta (B.1.617.2) variant of SARS-CoV-2. Our findings support the ongoing roll-out of this vaccine to help control the spread of SARS-CoV-2, while continuing the emphasis on adherence to non-pharmacological measures. FUNDING: None. TRANSLATION: For the Hindi translation of the abstract see Supplementary Materials section.

Evaluation of the dose-effect association between the number of doses and duration since the last dose of COVID-19 vaccine, and its efficacy in preventing the disease and reducing disease severity: A single centre, cross-sectional analytical study from India.

AIMS: To evaluate the dose-effect association between COVID-19 vaccination and probability of turning RT-PCR positive and to assess the correlation between disease severity and vaccination status. METHODS: A single centre cross-sectional study was conducted amongst 583 individuals presenting to COVID-19 testing clinic and 55 hospitalized COVID-19 patients. Vaccination status was assessed by the number of doses and duration since the last dose. Disease severity was evaluated by the requirement of hospitalisation and ICU admission/death. The association between the vaccination status and development of disease and its severity were statistically analyzed. RESULTS: The mean age of the population was 36.6 years and 82.6% had no comorbidities. The odds of turning RT-PCR positive was 0.17(95% CI: 0.11-0.27) among the clinical suspects who had taken both doses of the vaccine at least 14 days before (fully vaccinated). The odds of hospitalisation was 0.12(95% CI: 0.03-0.45) and ICU admission/death was 0.07(95% CI: 0.01-0.36) among fully vaccinated individuals. The protective role of vaccination was observed to start 14 days after receiving the first dose. CONCLUSIONS: COVID-19 vaccination provides dose-dependent protection against the development of the disease. It also lowers the risk of hospitalisation and ICU admission/death in RT-PCR positive patients in a dose-dependent manner.

Microfilaria in human subcutaneous dirofilariasis: a case report.

Human subcutaneous dirofilariasis, a rare zoonosis is being increasingly reported from various parts of the world. Most of the reported cases have lesions in and around the eye. The adult female dirofilariae release microfilaria into the definitive host's blood. Various mosquitoes that serve as intermediate hosts such as Culex, Aedes and Anopheles take up the microfilariae (mf-L1) while feeding on an infected host. Microfilariae develop in the mosquitoes. The transmission to dogs or other hosts including humans occurs through mosquito bite during subsequent blood meal. Humans may be infected as aberrant (accidental) hosts, mainly by D. repens and D. immitis. D. repens usually resides subcutaneously, while D. immitis frequently ends up in the human lung. In human infections usually just one larva develops, which does not reach sexual maturity. In India, almost all reported cases of dirofilariasis in humans have involvement of face in the form of ocular dirofilariasis with a few reports on subcutaneous dirofilariasis. We report a case of human subcutaneous dirofilariasis, from western India, involving leg and showing microfilaria in tissue indicating presence of gravid female dirofilaria (sexual maturity). To the best of our knowledge, it is among rare cases of subcutaneous dirofilariasis wherein microfilariae have developed in human host.