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The aim of this study was to assess the immunogenicity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines among people living with HIV (PLWH) with severe immunosuppression, after a booster dose. The design was a case-control study nested in a prospective cohort of PLWH. All patients with CD4 cell count <200 cells/mm 3 who had received additional dose of messenger RNA (mRNA) COVID-19 vaccine, after a standard immunization scheme were included. Control group: patients age-and sex-matched, with CD4 ≥ 200 cells/mm 3 , in the ratio of 2:1. Antibody response to a booster dose (anti-S levels 33.8 ≥ BAU/mL) and neutralizing activity against SARS-CoV-2 B.1, B.1.617.2, and Omicron BA.1, BA.2, and BA.5 strains were assessed after the booster shot. Fifty-four PLWH were included, 18 with CD4 counts < 200 cells/mm 3 . Fifty-one (94%) showed response to a booster dose. Response was less frequent in PLWH with CD4 < 200 cells/mm 3 than in those with CD4 counts ≥ 200 cells/mm 3 (15 [83%] vs. 36 [100%], p = 0.033). In the multivariate analysis, CD4 counts ≥ 200 cells/mm 3 [incidence rate ratio (IRR) = 18.1 (95% confidence interval [CI]: 16.8-19.5), p < 0.001] was associated with a higher probability of showing antibody response. Neutralization activity against SARS-CoV-2 B.1, B.1.617, BA.1, and BA.2 strains was significantly inferior among individuals with CD4 counts < 200 cells/mm 3 . In conclusion, among PLWH with CD4 counts < 200 cells/mm 3 , the immune response elicited by mRNA additional vaccine dose is reduced.

Objective To study the prevalence of transmitted drug resistance (TDR) to INSTIs and NRTIs, and of clinically relevant resistance (CRR), in newly-diagnosed people with HIV (PWH) naïve to antiretroviral therapy (ART) in Europe. Methods MeditRes HIV is a consortium that includes ART naïve PWH newly diagnosed in France, Greece, Italy, Portugal, and Spain during the years 2018-2021. Reverse transcriptase (RT) and Integrase (INSTI) sequences were provided by participating centers. To evaluate the prevalence of surveillance drug resistance mutations (SDRM) we used the CPR tools from Stanford HIV-website. To evaluate clinically relevant resistance (CRR), defined as any resistance level &gt;= 3, we used the Stanford v.9.1HIVDB Algorithm. Results We included 2705 PWH, 72% men, median age of 37 (IQR, 30-48); 43.7% infected by non-B subtypes. The prevalence of INSTI-SDRMs was 0.30% (T66I, T66A, E92Q, E138T, E138K, Y143R, S147G and R263K, all n = 1), and of NRTI-SDRMs was 5.77% (M184V n = 23, 0.85%; M184I n = 5, 0.18%; K65R/N n = 3, 0.11%; K70E n = 2, 0.07%; L74V/I n = 5, 0.18%; any TAMs n = 118, 4.36%). INSTI-CRR was 2.33% (0.15% dolutegravir/bictegravir; 2.29% raltegravir/elvitegravir), and 1.74% to first-line NRTIs (0.89% tenofovir/tenofovir alafenamide fumarate; 1.74% abacavir; 1.07% lamivudine/emtricitabine). Conclusions We present the most recent data on TDR to integrase based first-line regimens in Europe. Given the low prevalence of CRR to second generation integrase inhibitors and to first-line NRTIs, in the years 2018-2021 it is unlikely that newly diagnosed PWH in MeditRes countries would present with baseline resistance to a first-line regimen based on second generation integrase inhibitors.

Importance: The actual demand on SARS-CoV-2 diagnosis is a current challenge for clinical laboratories. Sample pooling may help to ameliorate workload in clinical laboratories. Objective: to evaluate the efficacy of sample pooling compared to the individual analysis for the diagnosis of CoVID-19, by using different commercial platforms for nucleic acid extraction and amplification. Design and settings: observational, prospective, multicentre study across 9 Spanish clinical microbiology laboratories including SARS-CoV-2 RNA testing performed in April 2020, during the first three days after acceptance to participate. Participants and Methods: 3519 naso-oro-pharyngeal samples received at the participating laboratories were processed individually and in pools (351 pools) according to the existing methodology in each of the centres. Results: We found that 253 pools (2519 samples) were negative, and 99 pools (990 samples) were positive; with 241 positive samples (6.85%), our pooling strategy would have saved 2167 PCR tests. For 29 pools (made out of 290 samples) we found discordant results when compared to their correspondent individual samples: in 24/29 pools (30 samples), minor discordances were found; for five pools (5 samples), we found major discordances. Sensitivity, specificity, positive and negative predictive values for pooling were 97.93%, 100%, 100% and 99.85% respectively; accuracy was 99.86% and kappa concordant coefficient was 0.988. As a result of the sample dilution effect of pooling, a loss of 2-3 Cts was observed for E, N or RdRP genes. Conclusion: we show a high efficiency of pooling strategies for SARS-CoV-2 RNA testing, across different RNA extraction and amplification platforms, with excellent performance in terms of sensitivity, specificity, and positive and negative predictive values. We believe that our results may help clinical laboratories to respond to the actual demand and clinical need on SARS-CoV-2 testing, especially for the screening of low prevalence populations.