Prospective assessment of humoral and cellular immune responses to a 3rd COVID-19 mRNA vaccine dose among immunocompromised individuals.

BACKGROUND: Improved COVID-19 prevention is needed for immunocompromised individuals. METHODS: Prospective study of healthcare workers (HCW) and immunocompromised participants with baseline serology following 2 mRNA vaccines and who were retested after dose 3 (D3); multivariable regression was used to identify predictors of serological responses. IFNγ/TNFα T-cell responses were assessed in a subset. RESULTS: 536 participants were included: 492 immunocompromised [(206 solid organ transplant (SOT), 128 autoimmune, 80 hematologic malignancy (HM), 48 solid tumor, 25 HIV], 44 HCW. D3 significantly increased Spike IgG levels among all, but SOT and HM participants had the lowest median antibody levels post-D3 (increase from 0.09 to 0.83 and 0.27 to 1.92, respectively), versus HCW and persons with HIV, autoimmune conditions, and solid tumors (increases from 4.44 to 19.79, 2.9 to 15.75, 3.82 to 16.32, and 4.1 to 25.54, respectively). Seropositivity post-D3 was lowest for SOT (49.0%) and HM (57.8%), versus others (>90% seropositive). Neutralization post-D3 was lowest among SOT and HM. Predictors of lower antibody levels included low baseline levels and shorter intervals between vaccines. T-cell responses against Spike increased significantly among HCW and non-significantly among immunocompromised individuals. CONCLUSIONS: D3 significantly improves serological but not T-cell responses among immunocompromised individuals. SOT and HM patients have suboptimal responses to D3.

Prospective Evaluation of Coronavirus Disease 2019 (COVID-19) Vaccine Responses Across a Broad Spectrum of Immunocompromising Conditions: the COVID-19 Vaccination in the Immunocompromised Study (COVICS).

BACKGROUND: We studied humoral responses after coronavirus disease 2019 (COVID-19) vaccination across varying causes of immunodeficiency. METHODS: Prospective study of fully vaccinated immunocompromised adults (solid organ transplant [SOT], hematologic malignancy, solid cancers, autoimmune conditions, human immunodeficiency virus [HIV]) versus nonimmunocompromised healthcare workers (HCWs). The primary outcome was the proportion with a reactive test (seropositive) for immunoglobulin G to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) receptor-binding domain. Secondary outcomes were comparisons of antibody levels and their correlation with pseudovirus neutralization titers. Stepwise logistic regression was used to identify factors associated with seropositivity. RESULTS: A total of 1271 participants enrolled: 1099 immunocompromised and 172 HCW. Compared with HCW (92.4% seropositive), seropositivity was lower among participants with SOT (30.7%), hematological malignancies (50.0%), autoimmune conditions (79.1%), solid tumors (78.7%), and HIV (79.8%) (P < .01). Factors associated with poor seropositivity included age, greater immunosuppression, time since vaccination, anti-CD20 monoclonal antibodies, and vaccination with BNT162b2 (Pfizer) or adenovirus vector vaccines versus messenger RNA (mRNA)-1273 (Moderna). mRNA-1273 was associated with higher antibody levels than BNT162b2 or adenovirus vector vaccines after adjusting for time since vaccination, age, and underlying condition. Antibody levels were strongly correlated with pseudovirus neutralization titers (Spearman r = 0.89, P < .0001), but in seropositive participants with intermediate antibody levels, neutralization titers were significantly lower in immunocompromised individuals versus HCW. CONCLUSIONS: Antibody responses to COVID-19 vaccines were lowest among SOT and anti-CD20 monoclonal recipients, and recipients of vaccines other than mRNA-1273. Among those with intermediate antibody levels, pseudovirus neutralization titers were lower in immunocompromised patients than HCWs. Additional SARS-CoV-2 preventive approaches are needed for immunocompromised persons, which may need to be tailored to the cause of immunodeficiency.

Clinical and Virologic Outcomes Following Initiation of Antiretroviral Therapy Among Seroconverters in the Microbicide Trials Network-020 Phase III Trial of the Dapivirine Vaginal Ring.

BACKGROUND: A vaginal ring containing dapivirine, a non-nucleoside human immunodeficiency virus (HIV)-1 reverse transcriptase inhibitor (NNRTI), was safe and effective in preventing HIV-1 infection in African women. We examined the impact of dapivirine ring use at the time of HIV-1 acquisition on subsequent HIV-1 disease progression and responses to NNRTI-containing antiretroviral therapy (ART). METHODS: HIV-1 disease progression and virologic failure following initiation of ART were assessed among women who acquired HIV-1 while participating in Microbicide Trials Network-020, a randomized, placebo-controlled trial of a monthly, dapivirine vaginal ring. RESULTS: Among the 158 participants who acquired HIV-1 (65 dapivirine, 93 placebo), no differences between dapivirine and placebo participants were observed in CD4+ cell counts or plasma HIV-1 RNA over the first year after infection (prior to ART). During follow-up, 100/158 (63%) participants initiated NNRTI-containing ART (dapivirine: 39/65; placebo: 61/93); the median time to HIV-1 RNA <200 copies/ml was approximately 90 days for both dapivirine and placebo ring recipients (log-rank P = .40). Among the 81 participants with at least 6 months of post-ART follow-up, 19 (24%) experienced virologic failure (dapivirine: 6/32, 19%; placebo: 13/39, 27%; P = .42). CONCLUSIONS: The acquisition of HIV-1 infection during dapivirine or placebo treatment in ASPIRE did not lead to differences in HIV-1 disease progression. After the initiation of NNRTI-containing ART, dapivirine and placebo participants had similar times to virologic suppression and risks of virologic failure. These results provide reassurance that NNRTI-based ART regimens are effective among women who acquired HIV-1 while receiving the dapivirine vaginal ring. CLINICAL TRIALS REGISTRATION: NCT016170096 and NCT00514098.

Frequent cross-resistance to rilpivirine among subtype C HIV-1 from first-line antiretroviral therapy failures in South Africa.

Background Rilpivirine (TMC278LA) is a promising drug for pre-exposure prophylaxis of HIV-1 because of its sub-nanomolar potency and long-acting formulation; however, increasing transmission of non-nucleoside reverse transcriptase inhibitor-resistant HIV-1 with potential cross-resistance to rilpivirine could reduce its preventive efficacy. This study investigated rilpivirine cross-resistance among recombinant subtype C HIV-1 derived from 100 individuals failing on first-line non-nucleoside reverse transcriptase inhibitor-containing antiretroviral therapy in South Africa whose samples were sent for routine HIV-1 drug resistance testing to Lancet Laboratories (Johannesburg, South Africa). Methods Plasma samples were selected from individuals with HIV-1 RNA > 10,000 copies/ml and ≥1 non-nucleoside reverse transcriptase inhibitor-resistance mutation in reverse transcriptase. Recombinant HIV-1LAI-containing bulk-cloned full-length reverse transcriptase sequences from plasma were assayed for susceptibility to nevirapine (NVP), efavirenz (EFV) and rilpivirine in TZM-bl cells. Fold-change (FC) decreases in drug susceptibility were calculated against a mean IC50 from 12 subtype C HIV-1 samples from treatment-naïve individuals in South Africa. Cross-resistance was evaluated based on biological cutoffs established for rilpivirine (2.5-FC) and the effect of mutation combinations on rilpivirine phenotype. Results Of the 100 samples from individuals on failing antiretroviral therapy, 69 had 2.5- to 75-fold decreased susceptibility to rilpivirine and 11 had >75-fold resistance. Rilpivirine resistance was strongly associated with K103N especially in combination with other rilpivirine-associated mutations. Conclusion The frequently observed cross-resistance of HIV-1 suggests that the preventive efficacy of TMC278LA pre-exposure prophylaxis could be compromised by transmission of HIV-1 from individuals with failure of first-line non-nucleoside reverse transcriptase inhibitor-containing antiretroviral therapy.

Future technologies for monitoring HIV drug resistance and cure.

PURPOSE OF REVIEW: Sensitive, scalable and affordable assays are critically needed for monitoring the success of interventions for preventing, treating and attempting to cure HIV infection. This review evaluates current and emerging technologies that are applicable for both surveillance of HIV drug resistance (HIVDR) and characterization of HIV reservoirs that persist despite antiretroviral therapy and are obstacles to curing HIV infection. RECENT FINDINGS: Next-generation sequencing (NGS) has the potential to be adapted into high-throughput, cost-efficient approaches for HIVDR surveillance and monitoring during continued scale-up of antiretroviral therapy and rollout of preexposure prophylaxis. Similarly, improvements in PCR and NGS are resulting in higher throughput single genome sequencing to detect intact proviruses and to characterize HIV integration sites and clonal expansions of infected cells. SUMMARY: Current population genotyping methods for resistance monitoring are high cost and low throughput. NGS, combined with simpler sample collection and storage matrices (e.g. dried blood spots), has considerable potential to broaden global surveillance and patient monitoring for HIVDR. Recent adaptions of NGS to identify integration sites of HIV in the human genome and to characterize the integrated HIV proviruses are likely to facilitate investigations of the impact of experimental 'curative' interventions on HIV reservoirs.

Should we fear resistance from tenofovir/emtricitabine preexposure prophylaxis?

PURPOSE OF REVIEW: To review current data on HIV-1 resistance arising from the use of fixed dose combination tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) for preexposure prophylaxis (PrEP) to prevent HIV-1 infection. RECENT FINDINGS: Resistance to tenofovir (TNV) or FTC is infrequently selected by TDF/FTC PrEP if started before HIV-1 infection has occurred, but is much more common when inadvertently started during undiagnosed acute infection. Mathematical modeling predicts that the number of HIV-1 infections averted by the use of PrEP far exceeds the increase in drug-resistant infections that could occur from PrEP. Studies in macaques show that TNV-resistant virus but not FTC-resistant virus can cause breakthrough infection despite TDF/FTC PrEP. FTC resistance with M184 V/I occurs more frequently than TFV resistance with K65R in seroconverters from clinical trials of TDF/FTC PrEP. SUMMARY: The benefit of preventing HIV-1 infections with TDF/FTC PrEP far outweighs the risk of drug-resistant infection, provided PrEP is not started in persons with undiagnosed HIV-1 infection. We should respect but not fear HIV-1 resistance from TDF/FTC PrEP and recognize that most TNV or FTC resistance will arise from its use for antiretroviral therapy (ART). Preventing ART failure or detecting it early is most important for preventing the spread of HIV-1 resistance to TDF/FTC and preserving its effectiveness for both PrEP and ART.

Y chromosome and HIV DNA detection in vaginal swabs as biomarkers of semen and HIV exposure in women.

BACKGROUND: The inability to quantify sexual exposure to HIV limits the power of HIV prevention trials of vaccines, microbicides, and preexposure prophylaxis in women. We investigated the detection of HIV-1 and Y chromosomal (Yc) DNA in vaginal swabs from 83 participants in the HPTN 035 microbicide trial as biomarkers of HIV exposure and unprotected sexual activity. METHODS: One hundred forty-three vaginal swabs from 85 women were evaluated for the presence of Yc DNA (Quantifiler Duo DNA quantification kit; Applied Biosystems) and total HIV-1 DNA (single-copy in-house quantitative polymerase chain reaction assay). Y DNA detection was paired with self-reported behavioral data with regard to recent coitus (≤1 week before collection) and condom usage (100% vs. <100% compliance). RESULTS: Yc DNA was detected in 62 (43%) of 143 swabs. For the 126 visits at which both behavioral data and swabs were collected, Yc DNA was significantly more frequent in women reporting less than 100% condom usage (odds ratio, 10.69; 95% confidence interval, 2.27-50.32; P = 0.003). Notably, 27 (33%) of 83 swabs from women reporting 100% condom usage were positive for Yc DNA. HIV DNA was only detected in swabs collected postseroconversion. CONCLUSIONS: The use of Yc DNA in HIV prevention trials could reliably identify subgroups of women who have unprotected sexual activity and could provide valuable exposure-based estimates of efficacy.

Postexposure protection of macaques from vaginal SHIV infection by topical integrase inhibitors.

Coitally delivered microbicide gels containing antiretroviral drugs are important for HIV prevention. However, to date, microbicides have contained entry or reverse transcriptase inhibitors that block early steps in virus infection and thus need to be given as a preexposure dose that interferes with sexual practices and may limit compliance. Integrase inhibitors block late steps after virus infection and therefore are more suitable for post-coital dosing. We first determined the kinetics of strand transfer in vitro and confirmed that integration begins about 6 hours after infection. We then used a repeat-challenge macaque model to assess efficacy of vaginal gels containing integrase strand transfer inhibitors when applied before or after simian/human immunodeficiency virus (SHIV) challenge. We showed that gel containing the strand transfer inhibitor L-870812 protected two of three macaques when applied 30 min before SHIV challenge. We next evaluated the efficacy of 1% raltegravir gel and demonstrated its ability to protect macaques when applied 3 hours after SHIV exposure (five of six protected; P < 0.05, Fisher's exact test). Breakthrough infections showed no evidence of drug resistance in plasma or vaginal secretions despite continued gel dosing after infection. We documented rapid vaginal absorption reflecting a short pharmacological lag time and noted that vaginal, but not plasma, virus load was substantially reduced in the breakthrough infection after raltegravir gel treatment. We provide a proof of concept that topically applied integrase inhibitors protect against vaginal SHIV infection when administered shortly before or 3 hours after virus exposure.

Prevalence of HIV-1 drug resistance among women screening for HIV prevention trials in KwaZulu-Natal, South Africa (MTN-009).

BACKGROUND: A major concern with using antiretroviral (ARV)-based products for HIV prevention is the potential spread of drug resistance, particularly from individuals who are HIV-infected but unaware of their status. Limited data exist on the prevalence of HIV infection or drug resistance among potential users of ARV-based prevention products. METHODS: A cross-sectional study of reproductive-aged women who presented to screen for an HIV prevention trial was conducted at 7 clinical sites in Durban, South Africa. CD4+T cell counts, HIV-1 RNA levels and population sequencing of the protease and reverse transcriptase genes were performed for all women with 2 positive HIV rapid tests. Resistance mutations were identified using the Stanford Calibrated Population Resistance Tool. RESULTS: Of the 1073 evaluable women, 400(37%) were confirmed as HIV-infected. Of those, plasma HIV-1 RNA was detectable in 365/400(91%) and undetectable(<40 copies/ml) in 35/400(9%) women. 156 women(39%) were eligible for antiretroviral therapy (CD4+T cell counts<350 cells/mm(3)) and 50(13%) met criteria for AIDS(CD4<200 cells/mm(3)). Of 352 plasma samples(>200 copies/ml) analyzed for drug resistance, 26(7.4%) had nucleoside reverse transcriptase inhibitor (NRTI), non-nucleoside reverse transcriptase inhibitor (NNRTI) or protease inhibitor (PI) drug resistance mutations. Among those with resistance, 18/26 participants(62%) had single-class NNRTI resistance and 5/26(19%) had dual-class NRTI/NNRTI. Major mutations in reverse transcriptase included K65R(n = 1), L74I(n = 1), K103N(n = 19), V106M(n = 4), Y181C(n = 2), M184V(n = 4), and K219E/R(n = 2). Major PI-resistance mutations were rare: M46L(n = 1) and I85V(n = 1). All participants were infected with subtype C virus, except one infected with subtype A. CONCLUSIONS: In women from Durban, South Africa screening for an HIV prevention trial, the HIV prevalence was high (37%) and HIV drug resistance prevalence was above 5%. This study highlights the potential challenges faced when implementing an ARV-based prevention product that overlaps with first-line antiretroviral therapy. Effective screening to exclude HIV infection among women interested in uptake of ARV-based HIV prevention will be essential in limiting the spread of ARV resistance.

Plasma and mucosal HIV viral loads are associated with genital tract inflammation in HIV-infected women.

BACKGROUND: Systemic and mucosal inflammation may play a role in HIV control. A cross-sectional comparison was conducted among women in the Women's Interagency HIV Study to explore the hypothesis that compared with HIV-uninfected participants, women with HIV, and, in particular, those with high plasma viral load (PVL) have increased levels of mucosal and systemic inflammatory mediators and impaired mucosal endogenous antimicrobial activity. METHODS: Nineteen HIV-uninfected, 40 HIV-infected on antiretroviral therapy (ART) with PVL ≤ 2600 copies/mL (low viral load) (HIV-LVL), and 19 HIV-infected on or off ART with PVL >10,000 (high viral load) (HIV-HVL) were evaluated. Immune mediators and viral RNA were quantified in plasma and cervicovaginal lavage (CVL). The CVL antimicrobial activity was also determined. RESULTS: Compared to HIV-uninfected participants, HIV-HVL women had higher levels of mucosal but not systemic proinflammatory cytokines and chemokines, higher Nugent scores, and lower Escherichia coli bactericidal activity. In contrast, there were no significant differences between HIV-LVL and HIV-uninfected controls. After adjusting for PVL, HIV genital tract shedding was significantly associated with higher CVL concentrations of IL-6, IL-1ß, MIP-1α, and CCL5 (RANTES) and higher plasma concentrations of MIP-1α. High PVL was associated with higher CVL levels of IL-1ß and RANTES, as well as with higher Nugent scores, lower E. coli bactericidal activity, smoking, and lower CD4 counts; smoking and CD4 count retained statistical significance in a multivariate model. CONCLUSIONS: Further study is needed to determine if the relationship between mucosal inflammation and PVL is causal and to determine if reducing mucosal inflammation is beneficial.

Antiretroviral-based HIV prevention strategies for women.

Almost three decades have elapsed since researchers identified HIV as the cause of AIDS, with current estimates from UNAIDS that 33.4 million adults were living with HIV/AIDS in 2008. Two-thirds of this burden of disease is in Sub-Saharan Africa, and 60% of those infected are women. The disease still remains incurable and current prevention strategies including abstinence, male/female condom use and male circumcision are only partially effective. New strategies to curb the epidemic are urgently needed. Scientists are diligently exploring HIV prevention methods that are safe, effective and affordable. These new biological interventions include oral pre-exposure prophylaxis using oral antiretroviral (ARV) drugs, ARV treatment in HIV-infected persons to reduce transmission and topical ARV-based microbicide formulations.