Genome characterization of monkeypox cases detected in India: Identification of three sub clusters among A.2 lineage

Since May 2022, Monkeypox, a zoonotic Orthopox DNA virus was reported in more than 102 countries indicating expansion of its geographic range. We analyzed the complete genomes sequences of Monkeypox cases from Kerala (n=5 travelled from UAE) and Delhi (n=5 no travel history), India confirmed during July to August 2022. All the retrieved MPXV sequences from India covering 90 to 99% genome belong to A.2 lineage of clade IIb. The A.2 MPXV lineage divided in three sub clusters; first cluster Kerala n=5, Delhi n=2 aligned with the USA-2022 ON674051.1; while second of Delhi n=3 aligned with USA-2022 ON675438.1 and third consists of the UK, USA and Thailand. Recent update in MPXV lineage designated all the five sequences from Kerala as A.2.1. In addition to known 16 single nucleotide polymorphisms (SNPs) along with 13 APOBEC3 cytosine deaminase activity determined specific lineage defining mutations in A.2 lineage, 25 additional APOBEC3 mutations were found in 10 reported sequences. The study emphasizes need of enhancing genomic surveillance to understand the mutation and its linkage.

Protective efficacy of COVAXIN(R) against Delta and Omicron variants in hamster model

The immunity acquired after natural infection or vaccinations against SARS-CoV-2 tend to wane with time. Vaccine effectiveness also varies with the variant of infection. Here, we compared the protective efficacy of COVAXIN(R) following 2 and 3 dose immunizations against the Delta variant and also studied the efficacy of COVAXIN(R) against Omicron variants in a Syrian hamster model. The antibody response, clinical observations, viral load reduction and lung disease severity after virus challenge were studied. Protective response in terms of the reduction in lung viral load and lung lesions were observed in both the 2 dose as well as 3 doses COVAXIN(R) immunized group when compared to placebo group following the Delta variant challenge. In spite of the comparable neutralizing antibody response against the homologous vaccine strain in both the 2 dose and 3 dose immunized groups, considerable reduction in the lung disease severity was observed in the 3 dose immunized group post Delta variant challenge indicating the involvement of cell mediated immune response also in protection. In the vaccine efficacy study against the Omicron variants i.e., BA.1 and BA.2, lesser virus shedding, lung viral load and lung disease severity were observed in the immunized groups in comparison to the placebo groups. The present study shows that administration of COVAXIN(R) booster dose will enhance the vaccine effectiveness against the Delta variant infection and give protection against the Omicron variants BA.1.1 and BA.2.

Persistence of immunity and impact of a third (booster) dose of an inactivated SARS-CoV-2 vaccine, BBV152; a phase 2, double-blind, randomised controlled trial

BackgroundNeutralising antibody responses to SARS-CoV-2 vaccines have been reported to decline within 6 months of vaccination, particularly against Variants of Concern (VOC). We assessed the immunogenicity and safety of a booster dose of BBV152 administered 6 months after the second of a two-dose primary vaccination series. MethodsIn an ongoing phase 2 trial (ClinicalTrials.gov: NCT04471519) the protocol was amended after six months to re-consent and randomise 184 previously vaccinated participants to receive a third dose of vaccine or placebo on Day 215. The primary outcome was to measure neutralising antibody titres by plaque-reduction neutralisation test (PRNT50) four weeks after the booster; safety as serious adverse events (SAE) was the key secondary outcome. FindingsFour weeks after a second BBV152 vaccination geometric mean titres (GMTs) of neutralising antibodies were 197{middle dot}0 PRNT50 (95% CI: 155{middle dot}6-249{middle dot}4); this level declined to 23{middle dot}9 PRNT50 (14{middle dot}0-40{middle dot}6) six months later, with a seroconversion rate of 75{middle dot}4% (95% CI: 68{middle dot}4-81{middle dot}6). Four weeks after booster vaccination the GMT increased on Day 243 to 746{middle dot}6 PRNT50 (514{middle dot}9-1081) compared with 100{middle dot}7 PRNT50 (43{middle dot}6-232{middle dot}6) in the placebo group. Corresponding seroconversion rates were 98{middle dot}7% (92{middle dot}8-99{middle dot}9) and 79{middle dot}8% (69{middle dot}6-87{middle dot}8). Increased titres in the placebo group were attributed to natural infection as the study was conducted during the second wave of COVID-19 in India. PRNT50 titres against the SARS-CoV-2 variants increased--Alpha (32{middle dot}6-fold), Beta (161{middle dot}0-fold), Delta (264{middle dot}7-fold), and Delta plus (174{middle dot}2-fold)--after the booster vaccination. We found that vaccine induces both memory B and T cells with a distinct AIM+ specific CD4+T central and effector memory phenotype, including CD8+ TEMRA phenotype. Reactogenicity after vaccine and placebo was minimal and comparable, and no SAEs were reported. InterpretationSix months after a two-dose BBV152 vaccination series cell mediated immunity and neutralising antibodies to both homologous (D614G) and heterologous strains (Alpha, Beta, Delta and Delta plus) persisted above baseline, although the magnitude of the responses had declined. Neutralising antibodies against homologous and heterologous SARS-CoV-2 variants increased 19- to 97-fold after a third vaccination. Booster BBV152 vaccination is safe and may be necessary to ensure persistent immunity to prevent breakthrough infections. FundingThis work was supported and funded by Bharat Biotech International Limited.

Substantial immune response in Omicron infected breakthrough and unvaccinated individuals against SARS-CoV-2 variants of concerns

The recent emergence of highly mutated SARS-CoV-2 Omicron variant has debilitating effect on public health system of the affected countries worldwide. Currently India is facing third wave of COVID-19 pandemic and going through a severe crisis. Within short span of time, the variant has shown high transmissibility and capability of evading the immune response generated against natural infection and vaccination. The immune escape potential of Omicron is a serious concern and further needs to be explored. In the present study, we have assessed the IgG and neutralizing antibody (NAb) response in breakthrough individuals vaccinated with two doses ChAdOx1 nCoV-19 vaccine (n=25), breakthrough individuals vaccinated with two doses of BNT162b2 mRNA vaccine (n=8) and unvaccinated individuals (n=6). All these individuals were infected with Omicron variant. The IgG antibody activity in the sera of the ChAdOx1 nCoV-19 and BNT162b2 mRNA breakthrough individuals was comparable with S1-RBD, while it was lesser in BNT162b2 mRNA breakthrough individuals with N protein and inactivated whole antigen IgG ELISA. BNT162b2 mRNA breakthrough individuals showed moderate reduction in NAb GMTs compared to ChAdOx1 nCoV-19 against Alpha, Beta and Delta. However, 3-fold higher reduction was observed with omicron variant in BNT162b2 mRNA than ChAdOx1 nCoV-19. Apparently, Alpha variant was modestly resistant to the sera of unvaccinated individuals than Beta, Delta and Omicron. Our study demonstrated substantial immune response in the individuals infected with Omicron. The neutralizing antibodies could effectively neutralize the Omicron and other VOCs including the most prevalent Delta variant.

An in vitro and in vivo approach for the isolation of Omicron variant from human clinical specimens

Due to failure of virus isolation of Omicron variant in Vero CCL-81 from the clinical specimens of COVID-19 cases, we infected Syrian hamsters and then passage into Vero CCL-81 cells. The Omicron sequences were studied to assess if hamster could incorporate any mutation to changes its susceptibility. L212C mutation, Tyrosine 69 deletion, and C25000T nucleotide change in spike gene and absence of V17I mutation in E gene was observed in sequences of hamster passage unlike human clinical specimen and Vero CCL-81 passages. No change was observed in the furin cleavage site in any of the specimen sequence which suggests usefulness of these isolates in future studies.

Detection of the omicron variant in international travellers and their family contacts in India

HighlightsWith the emergence of the Variant of Concern, omicron (B.1.1.529), India has enhanced genomic surveillance in international travellers. The omicron variant was detected in 59 cases from different States; 40 from Maharashtra, 17 from Rajasthan and one each from Gujrat and Tamil Nadu. The positive cases and their contacts were asymptomatic and genomic surveillance could identify two clusters, one from Maharashtra and another from Rajasthan.

Nipah virus outbreak in Kerala state, India amidst of COVID-19 pandemic

BackgroundWe report here a Nipah virus (NiV) outbreak in Kozhikode district of Kerala state, India which had caused fatal encephalitis in an adolescent male and the outbreak response which led to the successful containment of the disease and the related investigations. MethodsQuantitative real-time RT-PCR, ELISA based antibody detection and whole genome sequencing were performed to confirm the Nipah virus infection. Contacts of the index case were traced and isolated based on risk categorization. Bats from the areas near the epicenter of the outbreak were sampled for throat swabs, rectal swabs and blood samples for Nipah virus screening by real time RT-PCR and anti-Nipah virus bat IgG ELISA. Plaque reduction neutralization test was performed for the detection of neutralizing antibodies. ResultsNipah viral RNA and anti-NiV IgG antibodies were detected in the serum of the index case. Rapid establishment of an onsite NiV diagnostic facility and contact tracing helped in quick containment of the outbreak. NiV sequences retrieved from the clinical specimen of the index case formed a sub-cluster with the earlier reported Nipah I genotype sequences from India with more than 95% similarity. Anti-NiV IgG positivity could be detected in 21% of Pteropus medius and 37.73% of Rousettus leschenaultia. Neutralizing antibodies against NiV could be detected in P.medius. ConclusionsStringent surveillance and awareness campaigns needs to be implemented in the area to reduce human-bat interactions and minimize spill over events which can lead to sporadic outbreaks of NiV.

ZRC3308 monoclonal antibody cocktail shows protective efficacy in Syrian hamsters against SARS-CoV-2 infection

We have developed a monoclonal antibody (mAb) cocktail (ZRC-3308) comprising of ZRC3308-A7 and ZRC3308-B10 in the ratio 1:1 for COVID-19 treatment. The mAbs were designed to have reduced immune effector functions and increased circulation half-life. mAbs showed good binding affinities to non-competing epitopes on RBD of SARS-CoV-2 spike protein and were found neutralizing SARS-CoV-2 variants B.1, B.1.1.7, B.1.351, B.1.617.2 and B.1.617.2 AY.1 in vitro. The mAb cocktail demonstrated effective prophylactic and therapeutic activity against SARS-CoV-2 infection in Syrian hamsters. The antibody cocktail appears to be a promising candidate for the prophylactic use and for therapy in early COVID-19 cases which have not progressed to severe disease.

Serendipitous COVID-19 Vaccine-Mix in Uttar Pradesh, India: Safety and Immunogenicity Assessment of a Heterologous Regime

Immunization program against COVID-19 in India started with two vaccines; AstraZenecas ChAdOx1-nCov-19 (termed Covishield in India) and inactivated whole virion BBV152 (Covaxin); homologous prime-boost approach was followed. However, eighteen individuals, under the national program, inadvertently received Covishield as the first jab and Covaxin as the second. We compared the safety and immunogenicity profile of them against that of individuals receiving either Covishield or Covaxin (n=40 in each group). Lower and similar adverse events following immunization in all three groups underlined the safety of the combination vaccine-regime. Immunogenicity profile against Alpha, Beta and Delta variants in heterologous group was superior; IgG antibody and neutralising antibody response of the participants was also significantly higher compared to that in the homologous groups. The findings suggest that immunization with a combination of an adenovirus vector platform-based vaccine followed by an inactivated whole virus vaccine was not only safe but also elicited better immunogenicity.

Comparable neutralization of SARS-CoV-2 Delta AY.1 and Delta in individuals sera vaccinated with BBV152

The recent emergence of the SARS-CoV-2 Variant of Concern, B.1.617.2 (Delta) variant and its high transmissibility has led to the second wave in India. BBV152, a whole-virion inactivated SARS-CoV-2 vaccine used for mass immunization in India, showed a 65.2% protection against the Delta variant in a double-blind, randomized, multicentre, phase 3 clinical trial. Subsequently, Delta has been further mutated to Delta AY.1, AY.2, and AY.3. Of these, AY.1 variant was first detected in India in April 2021 and subsequently from twenty other countries as well. Here, we have evaluated the IgG antibody titer and neutralizing potential of sera of COVID-19 naive individuals full doses of BBV152 vaccine, COVID-19 recovered cases with full dose vaccines and breakthrough cases post-immunization BBV152 vaccines against Delta, Delta AY.1 and B.1.617.3. A reduction in neutralizing activity was observed with the COVID-19 naive individuals full vaccinated (1.3, 1.5, 1.9-fold), COVID-19 recovered cases with full BBV152 immunization (2.5, 3.5, 3.8-fold) and breakthrough cases post-immunization (1.9, 2.8, 3.5-fold) against Delta, Delta AY.1 and B.1.617.3 respectively compared to B.1 variant. A minor reduction was observed in the neutralizing antibody titer in COVID-19 recovered cases full BBV152 vaccinated and post immunized infected cases compared to COVID-19 naive vaccinated individuals. However, with the observed high titers, the sera of individuals belonging to all the aforementioned groups they would still neutralize the Delta, Delta AY.1 and B.1.617.3 variants effectively.

Clinical characterization and Genomic analysis of COVID-19 breakthrough infections during second wave in different states of India

During March to June 2021 India has experienced a deadly second wave of COVID-19 with an increased number of post-vaccination breakthrough infections reported across the country. To understand the possible reason of these breakthroughs we collected 677 clinical samples (throat swab/ nasal swabs) of individuals who had received two doses (n=592) and one dose (n=85) of vaccines (Covishield and Covaxin,) and tested positive for COVID-19, from 17 states/Union Territories of country. These cases were telephonically interviewed and clinical data was analyzed. A total of 511 SARS-CoV-2 genomes were recovered with genome coverage of higher than 98% from both the cases. Analysis of both the cases determined that 86.69% (n=443) of them belonged to the Delta variant along with Alpha, Kappa, Delta AY.1 and Delta AY.2. The Delta variant clustered into 4 distinct sub-lineages. Sub-lineage-I had mutations: ORF1ab-A1306S, P2046L, P2287S, V2930L, T3255I, T3446A, G5063S, P5401L, A6319V and N-G215C; Sub-lineage -II : ORF1ab- P309L, A3209V, V3718A, G5063S, P5401L and ORF7a-L116F; Sub-lineage -III : ORF1ab- A3209V, V3718A, T3750I, G5063S, P5401L and Spike-A222V; Sub-lineage -IV ORF1ab- P309L, D2980N, F3138S and spike - K77T. This study indicated that majority of the clinical cases in the breakthrough were infected with the Delta variant and only 9.8% cases required hospitalization while fatality was observed in only 0.4% cases. This clearly suggests that the vaccination does provide reduction in hospital admission and mortality.

Efficacy, safety, and lot to lot immunogenicity of an inactivated SARS-CoV-2 vaccine (BBV152): a double-blind, randomised, controlled phase 3 trial

BackgroundWe report the clinical efficacy against COVID-19 infection of BBV152, a whole-virion inactivated SARS-CoV-2 vaccine formulated with a Toll-like receptor 7/8 agonist molecule adsorbed to alum (Algel-IMDG). MethodsWe did a double-blind, randomised, multicentre, phase 3 clinical trial in 25 Indian hospitals to evaluate the efficacy, safety, and immunological lot consistency of BBV152. Healthy adults (age 18-98 years) randomised 1:1 using a computer-generated randomisation scheme received two intramuscular doses of vaccine or placebo administered four weeks apart. The primary outcome was laboratory-confirmed symptomatic COVID-19, occurring at least 14 days after the second dose. Secondary outcomes were efficacy in sub-groups for age (18-< 60 years and [≥] 60 years) and in participants with pre-existing stable medical conditions. We also evaluated safety, reactogenicity, and consistency of immune responses for three consecutive manufacturing lots. FindingsBetween November 16, 2020 and January 7, 2021 we recruited 25,798 participants who were randomised to BBV152 or placebo groups; 24,419 received two doses of BBV152 (n = 12,221) or placebo (n = 12,198). In a case-driven analysis, 130 cases of symptomatic COVID-19 were reported in 16,973 (0{middle dot}77%) participants with follow-up at least two weeks after the second vaccination; 24 occurred in the vaccine group and 106 in placebo recipients giving an overall vaccine efficacy of 77{middle dot}8% (95% CI: 65{middle dot}2-86{middle dot}4). Sixteen cases, one vaccinee and 15 placebo recipients, met the severe symptomatic COVID-19 case definition giving a vaccine efficacy of 93{middle dot}4% (57{middle dot}1-99{middle dot}8). Efficacy against asymptomatic COVID-19 was 63{middle dot}6% (29{middle dot}0-82{middle dot}4). BBV152 conferred 65{middle dot}2% (95% CI: 33{middle dot}1-83{middle dot}0) protection against the SARS-CoV-2 Variant of Concern, B.1.617.2 (Delta). BBV152 was well tolerated with no clinically or statistically significant differences in the distributions of solicited, unsolicited, or serious adverse events between vaccine and placebo groups. No cases of anaphylaxis or vaccine-related deaths were reported. InterpretationBBV152 was immunogenic and highly efficacious against symptomatic and asymptomatic COVID-19 variant associated disease, particularly against severe disease in adults. Vaccination was well tolerated with an overall incidence of adverse events observed over a median of 146 days that was lower than that observed with other COVID-19 vaccines. FundingThis work was supported and funded by Bharat Biotech International Limited and partly co-funded by the Indian Council of Medical Research. Clinicaltrials.gov: NCT04641481

Neutralization of Delta variant with sera of Covishield vaccinees and COVID-19 recovered vaccinated individuals

The recent emergence of B.1.617 lineage has created grave public health problem in India. The lineage further mutated to generate sub-lineages B.1.617.1 (Kappa), B.1.617.2 (Delta), B.1.617.3. Apparently, the Delta variant has slowly dominated the other variants including B.1.617.1 (Kappa), B.1.617.2 (Delta), B.1.617.3. With this, World Health Organization has described this sub-lineage as variant of concern. The high transmissibility associated with Delta variant has led to second wave of pandemic in India which affected millions of people. Besides this, variant of concerns has been reported to show lower neutralization to several approved vaccines. This has led to breakthrough infections after completion of vaccination regimen. There is limited information available on the duration of protective immune response post-infection, vaccination or breakthrough infection with SARS-CoV-2. In this study, we have evaluated immune response in sera of the Covishield vaccinated individuals belonging to category: I. one dose vaccinated, II. two doses vaccinated, III. COVID-19 recovered plus one dose vaccinated, IV. COVID-19 recovered plus two doses vaccinated and V. breakthrough COVID-19 cases. The findings of the study demonstrated that the breakthrough cases and the COVID-19 recovered individuals with one or two dose of vaccine had relatively higher protection against Delta variant in comparison to the participants who were administered either one or two doses of Covishield. Prior vaccination results in less severe disease against subsequent infection provide evidence that both humoral and cellular immune response play an important role in protection.

Neutralization against B.1.351 and B.1.617.2 with sera of COVID-19 recovered cases and vaccinees of BBV152

Recently, multiple SARS-CoV-2 variants have been detected across the globe. The recent emergence of B.1.617 lineage has created serious public health problem in India. The high transmissibility was observed with this lineage which has led to daily increase in the number of SARS-CoV-2 infections. Apparently, the sub-lineage B.1.617.2 has slowly dominated the other variants including B1617.1, B.617.3 and B.1.1.7. With this, World Health Organization has described B.1.617.2 as variant of concern. Besides this, variant of concern B.1.351 has been also reported from India, known to showreducedefficacyfor many approved vaccines. With the increasing threat of the SARS-CoV-2 variants, it is imperative to assess the efficacy of the currently available vaccines against these variants. Here, we have evaluated the neutralization potential of sera collected from COVID-19 recovered cases (n=20) and vaccinees with two doses of BBV152 (n=17) against B.1.351 and B.1.617.2 compared to the prototype B.1 (D614G) variant.The finding of the study demonstrated a reduction in neutralization titers with sera of COVID-19 recovered cases(3.3-fold and 4.6-fold) and BBV152 vaccinees (3. 0 and 2.7 fold) against B.1.351 and B.1.617.2 respectively.Although, there is reduction in neutralization titer, the whole-virion inactivated SARS-CoV-2 vaccine (BBV152) demonstrates protective response against VOC B.1351 and B.1.617.2.

Isolation of SARS-CoV-2 B.1.1.28.2 P2 variant and pathogenicity comparison with D614G variant in hamster model

BackgroundConsidering the potential threat from emerging SARS-CoV-2 variants and the rising COVID-19 cases, SARS-CoV-2 genomic surveillance is ongoing in India. We report herewith the isolation of the P.2 variant (B.1.1.28.2) from international travelers and further its pathogenicity evaluation and comparison with D614G variant (B.1) in hamster model. MethodsVirus isolation was performed in Vero CCL81 cells and genomic characterization by next generation sequencing. The pathogenicity of the isolate was assessed in Syrian hamster model and compared with B.1 variant. ResultsB.1.1.28.2 variant was isolated from nasal/throat swabs of international travelers returned to India from United Kingdom and Brazil. The B.1.1.28.2 variant induced body weight loss, viral replication in the respiratory tract, lung lesions and caused severe lung pathology in infected Syrian hamster model in comparison, with B.1 variant infected hamsters. The sera from B.1.1.28.2 infected hamsters efficiently neutralized the D614G variant virus whereas 6-fold reduction in the neutralization was seen in case of D614G variant infected hamsters sera with the B.1.1.28.2 variant. ConclusionsB.1.1.28.2 lineage variant could be successfully isolated and characterization could be performed. Pathogenicity of the isolate was demonstrated in Syrian hamster model and in comparison, with B.1 variant was found more pathogenic. The findings of increased disease severity and neutralization reduction is of great concern and point towards the need for screening the vaccines for efficacy.

Neutralization potential of Covishield vaccinated individuals against B.1.617.1

Covishield comprises the larger proportion in the vaccination program in India. Hence, it is of utmost importance to understand neutralizing capability of vaccine against the B.1.617.1 variant which is considered to responsible for surge of the cases in India. The neutralizing-antibody (NAb) titer against B.1.167.1 and prototype B.1 variant (D614G) was determined of the vaccine sera (4 weeks after second dose) of COVID-19 naive subjects (n=43) and COVID-19 recovered subjects (n=18). The results demonstrated that sera of COVID-19 recovered subjects (n=18) who received two doses of Covishield have higher NAb response compared to the COVID-19 naive with a significant difference (p<0.0001) in NAb titer against B.1 and B.1.617.1 In-spite of reduction in the neutralizing titer against B.1.617.1 variant; Covishield vaccine-induced antibodies are likely to be protective to limit the severity and mortality of the disease in the vaccinated individuals.

SARS CoV-2 variant B.1.617.1 is highly pathogenic in hamsters than B.1 variant

BackgroundThe recent emergence of new SARS-CoV-2 lineage B.1.617 in India has been associated with a surge in the number of daily infections. This variant has combination of specific mutations L452R, E484Q and P681R reported to possibly enhance the transmissibility with likelihood of escaping the immunity. We investigated the viral load and pathogenic potential of B.1.617.1 in Syrian golden hamsters. MethodsTwo groups of Syrian golden hamsters (9 each) were inoculated intranasally with SARS CoV-2 isolates, B.1 (D614G) and B.1.617.1 respectively. The animals were monitored daily for the clinical signs and body weight. The necropsy of three hamsters each was performed on 3, 5- and 7-days post-infection (DPI). Throat swab (TS), nasal wash (NW) and organ samples (lungs, nasal turbinate, trachea) were collected and screened using SARS-CoV-2 specific Real-time RT-PCR. ResultsThe hamsters infected with B.1.617.1 demonstrated increased body weight loss compared to B.1 variant. The highest viral load was observed in nasal turbinate and lung specimens of animals infected with B.1.167.1 on 3 DPI. Neutralizing antibody (NAb) and IgG response in hamsters of both the groups were observed from 5 and 7 DPI respectively. However, higher neutralizing antibody titers were observed against B.1.167.1. Gross pathology showed pronounced lung lesions and hemorrhage with B.1.671 compared to B.1. ConclusionsB.1617.1 and B.1 variant varied greatly in their infectiousness, pathogenesis in hamster model. This study demonstrates higher pathogenicity in hamsters evident with reduced body weight, higher viral load in lungs and pronounced lung lesions as compared to B.1 variant. SummaryB.1.617.1 is the new SARS-CoV-2 lineage that emerged in India. Maximal body weight loss and higher viral load in hamsters infected with B.1.617.1. It caused pronounced lung lesions in hamsters compared to B.1 variant which demonstrates the pathogenic potential of B.1.617.1.

Neutralization of B.1.1.28 P2 variant with sera of natural SARS-CoV-2 infection and recipients of BBV152 vaccine

The emergence of new SARS-CoV-2 variants has been a serious threat to the public health system and vaccination program. The variant of concerns have been the under investigation for their neutralizing potential against the currently available COVID-19 vaccines. Here, we have determined the neutralization efficacy of B.1.1.28.2 variant with the convalescent sera of individuals with natural infection and BBV152 vaccination. The two-dose vaccine regimen significantly boosted the IgG titer and neutralizing efficacy against both B.1.1.28.2 and D614G variants compared to that seen with natural infection. The study demonstrated 1.92 and 1.09 fold reductions in the neutralizing titer against B.1.1.28.2 variant in comparison with prototype D614G variant with sera of vaccine recipients and natural infection respectively.

Convergent evolution of SARS-CoV-2 spike mutations, L452R, E484Q and P681R, in the second wave of COVID-19 in Maharashtra, India

As the global severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic expands, genomic epidemiology and whole genome sequencing are being constantly used to investigate its transmissions and evolution. In the backdrop of the global emergence of "variants of concern" (VOCs) during December 2020 and an upsurge in a state in the western part of India since January 2021, whole genome sequencing and analysis of spike protein mutations using sequence and structural approaches was undertaken to identify possible new variants and gauge the fitness of current circulating strains. Phylogenetic analysis revealed that the predominant clade in circulation was a distinct newly identified lineage B.1.617 possessing common signature mutations D111D, G142D, L452R, E484Q, D614G and P681R, in the spike protein including within the receptor binding domain (RBD). Of these, the mutations at residue positions 452, 484 and 681 have been reported in other globally circulating lineages. The structural analysis of RBD mutations L452R and E484Q along with P681R in the furin cleavage site, revealed that these may possibly result in increased ACE2 binding and rate of S1-S2 cleavage resulting in better transmissibility. The same two RBD mutations indicated decreased binding to select monoclonal antibodies (mAbs) and may affect their neutralization potential. Experimental validation against a wider panel of mAbs, sera from vaccinees and those that recovered from natural infection needs to be studied. The emergence of such local variants through the accumulation of convergent mutations during the COVID-19 second wave needs to be further investigated for their public health impact in the rest of the country and its possibility of becoming a VOC.

Neutralization of variant under investigation B.1.617 with sera of BBV152 vaccinees

The drastic rise in the number of cases in Maharashtra, India has created a matter of concern for public health experts. Twelve isolates of VUI lineage B.1.617 were propagated in VeroCCL81 cells and characterized. Convalescent sera of the COVID-19 cases and recipients of BBV152 (Covaxin) were able to neutralize VUI B.1.617.