Emerging SARS-CoV-2 variants of concern evade humoral immune responses from infection and vaccination

Emerging SARS-CoV-2 variants of concern (VOCs) pose a threat to human immunity induced by natural infection and vaccination. We assessed the recognition of three VOCs (B.1.1.7, B.1.351, and P.1) in cohorts of COVID-19 convalescent patients (n = 69) and Pfizer-BioNTech vaccine recipients (n = 50). Spike binding and neutralization against all three VOCs were substantially reduced in most individuals, with the largest four- to sevenfold reduction in neutralization being observed against B.1.351. While hospitalized patients with COVID-19 and vaccinees maintained sufficient neutralizing titers against all three VOCs, 39% of nonhospitalized patients exhibited no detectable neutralization against B.1.351. Moreover, monoclonal neutralizing antibodies show sharp reductions in their binding kinetics and neutralizing potential to B.1.351 and P.1 but not to B.1.1.7. These data have implications for the degree to which pre-existing immunity can protect against subsequent infection with VOCs and informs policy makers of susceptibility to globally circulating SARS-CoV-2 VOCs.

Emerging SARS-CoV-2 variants of concern evade humoral immune responses from infection and vaccination

Emerging SARS-CoV-2 variants pose a threat to human immunity induced by natural infection and vaccination. We assessed the recognition of three variants of concern (B.1.1.7, B.1.351 and P.1) in cohorts of COVID-19 patients ranging in disease severity (n = 69) and recipients of the Pfizer/BioNTech vaccine (n = 50). Spike binding and neutralization against all three VOC was substantially reduced in the majority of samples, with the largest 4-7-fold reduction in neutralization being observed against B.1.351. While hospitalized COVID-19 patients and vaccinees maintained sufficient neutralizing titers against all three VOC, 39% of non-hospitalized patients did not neutralize B.1.351. Moreover, monoclonal neutralizing antibodies (NAbs) show sharp reductions in their binding kinetics and neutralizing potential to B.1.351 and P.1, but not to B.1.1.7. These data have implications for the degree to which pre-existing immunity can protect against subsequent infection with VOC and informs policy makers of susceptibility to globally circulating SARS-CoV-2 VOC.

HIV drug resistance following a decade of the free antiretroviral therapy programme in India: A review

OBJECTIVE

The objective of this review was to assess the burden of HIV drug resistance mutations (DRM) in Indian adults exposed to first-line antiretroviral therapy (ART) as per national guidelines.

METHODS

An advanced search of the published literature on HIV drug resistance in India was performed in the PubMed and Scopus databases. Data pertaining to age, sex, CD4 count, viral load, and prevalence of nucleoside reverse transcriptase inhibitor (NRTI)/non-nucleoside reverse transcriptase inhibitor (NNRTI) DRM were extracted from each publication. Year-wise Indian HIV-1 reverse transcriptase (RT) sequences were retrieved from the Los Alamos HIV database and mutation analyses were performed. A time trend analysis of the proportion of sequences showing NRTI resistance mutations among individuals exposed to first-line ART was conducted.

RESULTS

Overall, 23 studies (1046 unique RT sequences) were identified indicating a prevalence of drug resistance to NRTI and NNRTI. The proportion of RT sequences with any DRM, any NRTI DRM, and any NNRTI DRM was 78.39%, 68.83%, and 73.13%, respectively. The temporal trend analysis of individual DRM from sequences retrieved during 2004-2014 indicated a rising trend in K65R mutations (p=0.013).

CONCLUSIONS

Although the overall burden of resistance against first-line ART agents remained steady over the study decade, periodic monitoring is essential. There is the need to develop an HIV-1 subtype C-specific resistance database in India.

Cross-sectional study of virological failure and multinucleoside reverse transcriptase inhibitor resistance at 12 months of antiretroviral therapy in Western India

The free antiretroviral therapy (ART) program in India has scaled up to register second largest number of people living with HIV/AIDS across the globe. To assess the effectiveness of current first-line regimen we estimated virological suppression on completion of 1 year of ART. The study describes the correlates of virological failure (VF) and multinucleoside reverse transcriptase inhibitor (NRTI) drug resistance mutations (DRMs).In this cross-sectional study conducted between June and August 2014, consecutive adults from 4 State sponsored ART clinics of western India were recruited for plasma viral load screening at 12 ± 2 months of ART initiation. Individuals with plasma viral load >1000 copies/mL were selected for HIV drug resistance (HIVDR) genotyping. Logistic regression analyses were performed to assess factors associated with VF and multi-NRTI resistance mutations. Criteria adopted for multi-NRTI resistance mutation were either presence of K65R or 3 or more thymidine analog mutations (TAMs) or presence of M184V along with 2 TAMs.Of the 844 study participants, virological suppression at 1 year was achieved in 87.7% of individuals. Factors significantly associated with VF (P < 0.005) were 12 months CD4 count of ≤100 cells/μL (adjusted OR -7.11), low reported adherence (adjusted OR -4.44), and those living without any partner (adjusted OR -1.98). In patients with VF, the prevalence of non-nucleoside reverse transcriptase inhibitor (NNRTI) DRM (78.75%) were higher as compared to NRTI (58.75%). Multi-NRTI DRMs were present in 32.5% of sequences and were significantly associated with CD4 count of ≤100 cells/μL at baseline (adjusted OR -13.00) and TDF-based failing regimen (adjusted OR -20.43). Additionally, low reported adherence was negatively associated with multi-NRTI resistance (adjusted OR -0.11, P = 0.015). K65R mutation was significantly associated with tenofovir (TDF)-based failing regimen (P < 0.001).The study supports early linkage of HIV-infected individuals to the program for ART initiation, adherence improvement, and introduction of viral load monitoring. With recent introduction of TDF-based regimen, the emergence of K65R needs to be monitored closely among HIV-1 subtype C-infected Indian population.

Outcome of patients on second line antiretroviral therapy under programmatic condition in India

Background

The National AIDS Control Organization of India has been providing free second line antiretroviral therapy (ART) since 2008. This observational study reports the survival and virologic suppression of patients on second-line ART under programmatic condition and type of mutations acquired by those failing therapy.

Methods

170 patients initiated on second-line therapy between 2008 and 2012 were followed up till 2013. Viral Load (VL) was repeated at 6 months for all patients and at 12 months for those with VL >400 copies/ml at 6 months. Adequate virological response was defined as plasma HIV-1 VL <400 copies/ml and virological failure was defined as VL >1000 copies/ml. Genotyping was done in 16 patients with virological failure.

Results

Out of 170 patients, 110 (64.7 %) were alive and on therapy and 35 (20.5 %) expired. In the first year the occurrence of death was 13.7 /100 person years while between1 and 5 year it was 3.88 /100 person years. In the first year, duration of immunological failure >12 months, weight <45 kg, WHO clinical stage 3 and 4 and WHO criteria CD4 count less than pretherapy baseline [hazard ratio HR 4.2. 15.8, 11.9 & 4.1 respectively] and beyond first year poor first and second line adherence and first line CD4 count < 200/μL [HR 5.2,15.8, 3.3 respectively] had high risk of death.

119/152 (78.2 %) had adequate virological response and 27/152 (17.7 %) had virological failure. High viral load at baseline and poor second line adherence (Odds Ratio 3.4 & 2.8 respectively) had increased risk of virological failure. Among those genotyped, 50 % had major Protease Inhibitor mutation (M46I commonest) however 87.5 % were still susceptible to darunavir.

Conclusions

Second line therapy has shown high early mortality but good virological suppression under programmatic conditions.

Evaluation of a cost effective in-house method for HIV-1 drug resistance genotyping using plasma samples

Objectives

Validation of a cost effective in-house method for HIV-1 drug resistance genotyping using plasma samples.

Design

The validation includes the establishment of analytical performance characteristics such as accuracy, reproducibility, precision and sensitivity.

Methods

The accuracy was assessed by comparing 26 paired Virological Quality Assessment (VQA) proficiency testing panel sequences generated by in-house and ViroSeq Genotyping System 2.0 (Celera Diagnostics, US) as a gold standard. The reproducibility and precision were carried out on five samples with five replicates representing multiple HIV-1 subtypes (A, B, C) and resistance patterns. The amplification sensitivity was evaluated on HIV-1 positive plasma samples (n = 88) with known viral loads ranges from 1000–1.8 million RNA copies/ml.

Results

Comparison of the nucleotide sequences generated by ViroSeq and in-house method showed 99.41±0.46 and 99.68±0.35% mean nucleotide and amino acid identity respectively. Out of 135 Stanford HIVdb listed HIV-1 drug resistance mutations, partial discordance was observed at 15 positions and complete discordance was absent. The reproducibility and precision study showed high nucleotide sequence identities i.e. 99.88±0.10 and 99.82±0.20 respectively. The in-house method showed 100% analytical sensitivity on the samples with HIV-1 viral load >1000 RNA copies/ml. The cost of running the in-house method is only 50% of that for ViroSeq method (112$ vs 300$), thus making it cost effective.

Conclusions

The validated cost effective in-house method may be used to collect surveillance data on the emergence and transmission of HIV-1 drug resistance in resource limited countries. Moreover, the wide applications of a cost effective and validated in-house method for HIV-1 drug resistance testing will facilitate the decision making for the appropriate management of HIV infected patients.

Evaluations of an in-house drug resistance method for HIV-1 drug resistance using ViroSeq™ 2.0 genotyping system as a gold standard

An in-house method was evaluated for its efficiency to detect the HIV-1 drug resistance mutations. This method was compared with the ViroSeq™ Genotyping System 2.0 (Celera Diagnostics, US) a gold standard. Sixty-five stored plasma samples, previously tested for HIV-1 drug resistance using the ViroSeq™ method were used to evaluate the in-house method. Out of the sixty five plasma samples, sixty were HIV-1 positive clinical samples; four samples from the Virology Quality Assessment (VQA) program and one positive control from the ViroSeq™ kit were used in this study. The sequences generated by the ViroSeq™ and an in-house method showed 99.5±0.5% and 99.7±0.4% (mean±SD) nucleotide and amino acid identity, respectively. Out of 214 Stanford HIVdb listed HIV-1 drug resistance mutations in the protease and reverse transcriptase regions, concordance was observed in 203 (94.9%), partial discordance in 11 (5.1%) and complete discordance was absent. The in-house primers are broadly sensitive in genotyping multiple HIV-1 group M subtypes. The amplification sensitivity of the in-house method was 1000 copies/ml. The evaluation of the in-house method provides results comparable with that of ViroSeq™ method thus, making the in-house method suitable for HIV-1 drug resistance testing in the developing countries.

Initial virologic response and HIV drug resistance among HIV-infected individuals initiating first-line antiretroviral therapy at 2 clinics in Chennai and Mumbai, India

Human immunodeficiency virus drug resistance (HIVDR) in cohorts of patients initiating antiretroviral therapy (ART) at clinics in Chennai and Mumbai, India, was assessed following World Health Organization (WHO) guidelines. Twelve months after ART initiation, 75% and 64.6% of participants at the Chennai and Mumbai clinics, respectively, achieved viral load suppression of <1000 copies/mL (HIVDR prevention). HIVDR at initiation of ART (P <.05) and 12-month CD4 cell counts <200 cells/μL (P <.05) were associated with HIVDR at 12 months. HIVDR prevention exceeded WHO guidelines (≥ 70%) at the Chennai clinic but was below the target in Mumbai due to high rates of loss to follow-up. Findings highlight the need for defaulter tracing and scale-up of routine viral load testing to identify patients failing first-line ART.

Surveillance of transmitted HIV type 1 drug resistance among HIV type 1-positive women attending an antenatal clinic in Kakinada, India

The World Health Organizations HIV Drug Resistance (WHO HIVDR) Threshold survey method was used to assess transmitted HIVDR in newly diagnosed HIV-1-infected primigravida women attending the Prevention of Parent to Child Transmission (PPTCT) centers in Kakinada, in whom it is likely that the infection had recently occurred. Out of the 56 consecutively collected eligible specimens, 51 were tested using the ViroSeq RT-PCR method (Abbott Germany) to obtain 47 consecutive sequences for the HIV-1 protease (PR) and reverse transcriptase (RT) region. As per the 2009 WHO list of mutations for surveillance of transmitted HIVDR, only one nonnucleoside reverse transcriptase inhibitor (NNRTI) mutation was detected at K101E from all specimens tested, suggesting a low prevalence (<5%) of resistance to NNRTIs and no mutations were detected at other sites, suggesting a low prevalence (<5%) of resistance to nucleoside reverse transcriptase inhibitors (NRTI) and protease inhibitors (PI) drug classes as well. Phylogenetic analysis showed all sequences belonged to HIV-1 subtype C. In the wake of antiretroviral treatment (ART) scale-up, future evaluation of transmitted HIVDR is essential in Kakinada as well as in other regions of India.

Transmitted HIV drug resistance among HIV-infected voluntary counseling and testing centers (VCTC) clients in Mumbai, India

A survey for transmitted HIV drug resistance (HIVDR) was conducted according to WHO guidelines among clients newly diagnosed with HIV-1 infection at two voluntary counseling and testing centers (VCTC) in Mumbai. HIVDR testing was performed using the ViroSeq RT-PCR method (Abbott). Out of 50 successfully amplified and sequenced specimens, analysis of the first 34 consecutively collected specimens revealed no nucleoside reverse transcriptase inhibitor, nonnucleoside reverse transcriptase inhibitor, or protease inhibitor mutations from the 2007 WHO list of mutations for surveillance of transmitted HIVDR, indicating that the prevalence of transmitted HIVDR to all three drug classes was <5% among recently infected VCTC clients in Mumbai. The phylogenetic analysis revealed that all samples belonged to HIV-1 subtype C. Continued ART program monitoring and further evaluation of transmitted HIV drug resistance in coming years are essential in Mumbai as well as in other regions of the country in which ART is being scaled up rapidly.