Detection of pre-existing neutralizing antibodies against Ad26 in HIV-1-infected individuals not responding to the Ad26.COV2.S vaccine

PURPOSE

The Ad26.COV2.S vaccine is a replication-incompetent human adenovirus type 26 vector encoding the SARS-CoV-2 spike protein. In a phase 1-2a trial, a single dose of Ad26.COV2.S induced SARS-CoV-2 spike-specific antibodies in ≥ 96% of healthy adults. To investigate vaccine immunogenicity in HIV-1-infection, we measured SARS-CoV-2 spike-specific antibodies in Ad26.COV2.S vaccinated HIV-1-infected patients and analyzed the presence of pre-existing Ad26 neutralizing antibodies.

METHODS

We included all Ad26.COV2.S vaccinated HIV-1-infected patients of Erlangen HIV cohort fulfilling all inclusion criteria. The study cohort consisted of 15 HIV-1-infected patients and three HIV-1-uninfected subjects who received the Ad26.COV2.S vaccine between April and November 2021. Pre-vaccination sera were collected between October 2014 and June 2021, post-vaccination sera between June and December 2021. Neutralizing antibodies towards Ad26 were determined by a FACS-based inhibition assay measuring the expression of SARS-CoV-2 spike and adenoviral proteins in HEK293T cells after in-vitro transduction with Ad26.COV2.S or the control ChAdOx1-S.

RESULTS

Six out of 15 HIV-1-infected patients failed to develop SARS-CoV-2-specific antibodies and four patients developed weak antibody responses after vaccination with Ad26.COV2.S. Pre-vaccination sera of four of the six vaccine non-responders showed neutralizing activity towards Ad26.COV2.S but not toward the ChAdOx1-S vaccine at 1:50 dilution. After Ad26.COV2.S vaccination, 17 of the 18 subjects developed strong Ad26-neutralizing activity and only one of the 18 subjects showed neutralizing activity towards the ChAdOx1-S vaccine.

CONCLUSION

Ad26.COV2.S vaccination showed a high failure rate in HIV-1-infected patients. Pre-existing immunity against Ad26 could be an important contributor to poor vaccine efficacy in a subgroup of patients.

Adaptation of the Australian Palliative Care Phase concept to the German palliative care context: a mixed-methods approach using cognitive interviews and cross-sectional data

BACKGROUND

Palliative care phases (stable, unstable, deteriorating, terminal and bereavement) are routinely used in Australia and the UK to describe the clinical situation of patients and their families and to evaluate the associated care plan. In addition, it serves as a benchmark developed by the Australian Palliative Care Outcome Collaboration (PCOC) and is used nationwide for comparisons between services. In Germany, the concept is not used consistently due to various translations. Furthermore, there is no nationwide systematic approach to routinely assess clinical outcomes in palliative care. The study aims to develop a German version of the palliative care phase definitions by adapting them culturally, and to examine the inter-rater reliability of the adjusted definitions with healthcare professionals.

METHODS

Mixed-methods approach: Cognitive interview study using 'think aloud' and verbal probing techniques and a consecutive multi-center cross-sectional study with two clinicians independently assigning the phase definitions. Interviewees/participants were selected through convenience and purposive sampling in specialist palliative care inpatient units, advisory and community services and in three specialist palliative care units with doctors, nursing staff and allied health professionals.

RESULTS

Fifteen interviews were conducted. Identified difficulties were: Some translated terms were 1) not self-explanatory (e.g. 'family/carer' or 'care plan') and (2) too limited to the medical dimension neglecting the holistic approach of palliative care. (3) Problems of comprehension regarding the concept in general occurred, e.g. in differentiating between the 'unstable' and 'deteriorating' phase. Inter-rater reliability was moderate (kappa = 0.44; 95% CI = 0.39-0.52). The assignment of the phase 'deteriorating' has caused the most difficulties.

CONCLUSION

Overall, the adapted palliative care phases are suitable to use in the German specialist palliative care setting. However, the concept of the phases is not self-explanatory. To implement it nationwide for outcome measurement/benchmarking, it requires further education, on-the-job training and experience as well as the involvement of healthcare professionals in implementation process. For the use of international concepts in different healthcare systems, a deeper discussion and cultural adaptation is necessary besides the formal translation.