The COVID-19 pandemic is a global health crisis that poses a great challenge to the public health system of affected countries. Safe and effective vaccines are needed to overcome this crisis. Here, we develop and assess the protective efficacy and immunogenicity of an inactivated SARS-CoV-2 vaccine in rhesus macaques. Twenty macaques were divided into four groups of five animals each. One group was administered a placebo, while three groups were immunized with three different vaccine candidates of BBV152 at 0 and 14 days. All the macaques were challenged with SARS-CoV-2 fourteen days after the second dose. The protective response was observed with increasing SARS-CoV-2 specific IgG and neutralizing antibody titers from 3^rd-week post-immunization. Viral clearance was observed from bronchoalveolar lavage fluid, nasal swab, throat swab and lung tissues at 7 days post-infection in the vaccinated groups. No evidence of pneumonia was observed by histopathological examination in vaccinated groups, unlike the placebo group which exhibited interstitial pneumonia and localization of viral antigen in the alveolar epithelium and macrophages by immunohistochemistry. This vaccine candidate BBV152 has completed Phase I/II (NCT04471519) clinical trials in India and is presently in phase III, data of this study substantiates the immunogenicity and protective efficacy of the vaccine candidates.

Indian J Med Res, Official publication of Indian Council of Medical Research,India

Men who have sex with men (MSM) who also report transactional sex (male sex workers or MSWs) are known to be at higher risk for HIV and sexually transmitted infections (STIs). The study aimed to profile socio-demographic characteristics and risk factors associated with high HIV prevalence among MSWs.

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) Delta variant (B.1.617.2), a variant of concern, was associated with the second wave of pandemic in India during March–May 2021. Delta variant has outpaced the other two sub-lineages Kappa (B.1.617.1) and B.1.617.3 and was responsible for 90% of the cases reported in India. ¹ It has spread across 112 countries and found to be more infectious than the Alpha, Beta and Gamma variants. Reduced neutralization has been reported with the sera of individuals vaccinated with BNT162b2, BBV152/Covaxin and chAdOx1-s against Delta variant in recent reports. ^{2, 3} Delta variant has also been identified as the leading cause of breakthrough infections globally among vaccinated individuals. ⁴

COVID-19 vaccination program was rolled out in India on January 16^th 2021. ¹ The whole virion inactivated BBV152 (Covaxin) and AstraZeneca’s ChAdOx1-nCov-19 (Covishield) were the two vaccines initially included under this program. ^{2, 3, 4, 5} Frontline workers including healthcare professionals, elderly above the age of 60 and adults with co-morbidity were prioritized for vaccination before reaching out to all the adults. During expansion of the aforementioned vaccination program, a group of participants in the northern state of Uttar Pradesh received Covishield (CS) as the first dose followed by inadvertent administration of Covaxin (CV) as the second dose. We studied the safety and immunogenicity of this heterologous prime-boost COVID-19 vaccination. A total of 98 vaccine recipients who had completed two weeks or more after the second dose of vaccine were included in this study. Three groups of participants were recruited during May to June 2021: heterologous group (n = 18, first dose CS, second dose CV administered at an interval of six weeks), among them, 11 were male (M/F:11/7) with a median age of 62 year (IQR 54.25–69.75). A comorbid condition (hypertension) was reported in one participant. Homologous CS group (n = 40, 22 were males and the rest were female (M/F:22/18) with a median age of 65.5 years (IQR 62–69) and co-morbidity was observed among 4 participants who received two CS-vaccine doses at six weeks interval. The homologous CV-group (n = 40, two vaccine doses administered at four weeks interval including 23 females (M/F:17/23) with a median age of 56 year (IQR 45.5–63) and 3 with co-morbidities ( Supplementary Table 1 ) ( Supplementary Figure S1 ).

We report the development and evaluation of safety and immunogenicity of a whole virion inactivated SARS-COV-2 vaccine (BBV152), adjuvanted with aluminium hydroxide gel (Algel), or a novel TLR7/8 agonist adsorbed Algel. We used a well-characterized SARS-CoV-2 strain and an established vero cell platform to produce large-scale GMP grade highly purified inactivated antigen, BBV152. Product development and manufacturing were carried out in a BSL-3 facility. Immunogenicity was determined at two antigen concentrations (3μg and 6μg), with two different adjuvants, in mice, rats, and rabbits. Our results show that BBV152 vaccine formulations generated significantly high antigen-binding and neutralizing antibody titers, at both concentrations, in all three species with excellent safety profiles. The inactivated vaccine formulation containing TLR7/8 agonist adjuvant-induced Th1 biased antibody responses with elevated IgG2a/IgG1 ratio and increased levels of SARS-CoV-2 specific IFN-γ+ CD4 T lymphocyte response. Our results support further development for Phase I/II clinical trials in humans.