Incidence of COVID-19 mRNA vaccine symptomatic breakthrough infections during Omicron circulation in adults with or without infection prior to vaccination

OBJECTIVES

COVID-19 vaccine breakthrough infections were frequently reported during circulation of the Omicron variant. The ANRS|MIE CoviCompareP study investigated these infections in adults vaccinated and boosted with BNT162b2 [Pfizer-BioNTech] and with/without SARS-CoV-2 infection before vaccination.

METHODS

In the first half of 2021, healthy adults (aged 18-45, 65-74 and 75 or older) received either one dose of BNT162b2 (n = 120) if they had a documented history of SARS-CoV-2 infection at least five months previously, or two doses (n = 147) if they had no history confirmed by negative serological tests. A first booster dose was administered at least 6 months after the primary vaccination, and a second booster dose, if any, was reported in the database. Neutralizing antibodies (NAbs) against the European (D614G) strain and the Omicron BA.1 variant were assessed up to 28 days after the first booster dose. A case-control analysis was performed for the 252 participants who were followed up in 2022, during the Omicron waves.

RESULTS

From January to October 2022, 78/252 (31%) had a documented symptomatic breakthrough infection after full vaccination: 21/117 (18%) in those who had been infected before vaccination vs. 57/135 (42%) in those who had not. In a multivariate logistic regression model, factors associated with a lower risk of breakthrough infection were older age, a higher number of booster doses, and higher levels of Omicron BA.1 NAb titers in adults with infection before vaccination, but not in those without prior infection.

CONCLUSION

Our results highlight the need to consider immune markers of protection in association with infection and vaccination history.

Low level of baseline resistance in recently HCV-infected men who have sex with men with high-risk behaviours

OBJECTIVES

Presence of baseline hepatitis C virus (HCV) resistance-associated substitutions (RASs) can impair treatment outcome of direct-acting antivirals. We investigated the prevalence of pre-treatment HCV resistance among recently HCV-infected men who have sex with men (MSM) with high risk behaviours, either human immunodeficiency virus (HIV) co-infected or at high risk of HIV acquisition and under pre-exposure prophylaxis (PrEP).

METHODS

NS5A and NS3 fragments were deep sequenced on pre-treatment samples of 72 subjects using Illumina MiSeq paired-end sequencing technology. Ultra-deep sequencing data were analysed by SmartGene® platform. RASs mentioned in the literature were analysed and interpreted depending on genotype (GT) at 10% cut-off.

RESULTS

HCV genotyping showed 36 (50.0%) GT1a, 31 (43.1%) GT4d and 5 (6.9%) GT3a infections. Fifty-five patients (76.4%) were co-infected with HIV and 15 (20.8%) received PrEP. In GT1a viruses, NS3 RASs were found in 4/30 viruses (13.3%; S122 G/N, R155 K and I170 V) and Q80 K polymorphism was present in 14/30 viruses (46.7%). No NS3 RASs were detected in GT4d and GT3a viruses. NS5A RASs were detected in 3/36 GT1a viruses (8.3%; Q30E/R, L31 M and H58 L). NS5A subtype-specific polymorphisms L30R and T58 P were found at high frequencies in 31/31 (100%) and 16/31 (51.6%) GT4d viruses, respectively. One RAS M31 L was also observed along with the polymorphisms L30R and T58 P. No NS5A RASs were detected in GT3a viruses.

CONCLUSION

A low level of RASs to NS3 and NS5A inhibitors in pre-treatment samples was detected in the study population. Our findings reassure the clinical management of HCV infection in this high-risk population.

Long-term effects of intermittent interleukin-2 therapy in chronic HIV-infected patients (ANRS 048-079 Trials)

OBJECTIVE

Interleukin (IL)-2 therapy leads to significant CD4 cell increases in HIV-infected patients. Since phase III trials are ongoing, studies supporting the long-term feasibility of this strategy are needed.

METHODS

We studied the long-term outcomes of 131 patients treated with IL-2 in two studies initiated either before (ANRS 048) or following (ANRS 079) the advent of HAART.

RESULTS

At the last assessment (median follow-up 3.4 years), these patients experienced a gain of 428 cells/microl and a decrease in plasma HIV RNA to 1.70 log10 copies/ml. In both studies, high CD4 cell counts were maintained with a median of ten 5-day cycles of subcutaneous IL-2. Median time since the last cycle was 2 years. At last assessment, 59% of 048 patients maintained a non-HAART regimen. Detailed analysis at week 170 showed that median CD4 cell counts were 856 (048) and 964 (079) cells/microl. This corresponded to a gain from baseline of 515 (048) and 627 (079) cells/microl. The median viral load decreases from baseline and corresponded to 1.70 (048) and 1.88 (079) log10 copies/ml. Comparisons across the studies showed that CD4 gains and viral load changes were similar whether HAART or non-HAART was used. The frequency of cycling, but not CD4 cell counts, viral loads or antiviral regimen at baseline, was predictive of long-term CD4 gain (P = 0.03).

CONCLUSION

Altogether, these observations support IL-2 as a long-term therapeutic strategy in HIV infection.

Neural circuitry and light responses of the dopamine amacrine cell of the turtle retina

PURPOSE

To understand the circuitry and electrophysiology of the dopamine cells in the turtle retina.

METHODS

Preembedding immunocytochemistry for tyrosine hydroxylase (Toh) was done on vibratome sections of turtle retina. Resultant Toh-immunoreactive (Toh-IR) amacrine cells were then serially thin-sectioned for analysis by electron microscopy (EM). Some sections of Toh-IR cells also were post-embedding immunostained for glycine and GABA content. Intracellular recordings and dye markings were made from the turtle eyecup and slice preparation to determine the light responses of cells called A28, which have the same morphology as Toh-IR amacrine cells.

RESULTS

Physiologically A28 cells were L-type (luminosity) and gave sustained depolarizing (ON-center) responses to light pulses. High intensity light pulses produced immediate transients and long depolarizations, lasting beyond the stimulus duration. An after-hyperpolarization and an antagonistic surround could be elicited. EM reconstruction of a Toh-IR cell revealed new circuitry over that described before (Pollard, J. & Eldred, W.D. (1990). J. Neurocytol. 19, 53-66). Bipolar ribbon synapses occurred in all three dendritic tiers. However, amacrine cell inputs dominated numerically (95% amacrine input, 5% bipolar input) many of them in a serial synaptic configuration. GABA+ inputs were seen but not glycine+ inputs. Output from Toh-IR profiles was primarily to large ganglion cell dendrites but also to bipolar cell axons, GABA-IR amacrines, unspecified amacrine cells and other Toh-IR dendrites.

CONCLUSIONS

The synaptology of the dopamine cells of the turtle retina suggests that sustained inhibitory amacrine cell pathways, including GABAergic pathways, are chiefly responsible for their response characteristics at low light levels. Conversely, at higher light intensities, transient excitatory amacrine cells probably have influence.