Meeting statement: Call to action for step-change in health behaviours.

Background: Enabling, supporting and promoting positive health-related behaviours is critical in addressing the major public health challenges of our time, and the multifaceted nature of behaviours requires an evidence-based approach. This statement seeks to suggest how a much-needed enhanced use of behavioural and cultural science and insights for health could be advanced. Study design and methods: and methods: Public health authorities of Europe and Central Asia and international partner organizations in September 2023 met in Copenhagen, Denmark, to discuss the way forward. Drawing on 1) country reporting to WHO, 2) interview study with public health authorities and 3) the meeting deliberations, this meeting statement was developed. Results: The meeting statement presents a joint call for step-change accelerated use of evidence-based approaches for health behaviours. Actionable next steps for public health authorities and international and regional development partners in health are presented. Conclusions: The way forward involves increased resource allocation, integration of behavioural insights into health strategies, advocacy through case and cost-effectiveness examples and capacity building.

Exploring nurses' experiences of a tailored intervention to increase MMR vaccine acceptance in a Somali community in Stockholm, Sweden: a qualitative interview study.

OBJECTIVES: To explore nurses' experiences of a tailored intervention that supported them with knowledge and tools to use during encounters and dialogue with parents with low vaccine acceptance. DESIGN: A qualitative study with in-depth interviews conducted in 2017. Data were analysed using thematic analysis. SETTING: This study was part of a multicomponent intervention targeting Somali parents and the nurses at child health centres in the Rinkeby and Tensta neighbourhoods of Stockholm. An area with documented low measles, mumps and rubella (MMR) vaccination coverage. Previous research has revealed that Somali parents in the community delayed MMR vaccination due to fear of autism despite lack of scientific evidence. The interventions were implemented in 2015-2017. PARTICIPANTS: Eleven nurses employed at the child health centres involved in the intervention participated in interviews. The tailored intervention targeting nurses included a series of seminars, a narrative film and an information card with key messages for distribution to parents. RESULTS: The qualitative analysis revealed an overarching theme: perception of improved communication with parents. Two underlying themes were identified: (1) feeling more confident to address parents' MMR vaccine concerns and (2) diverse tools as useful support to dispel myth and reduce language barriers. CONCLUSION: From the nurses' perspective, the tailored intervention was useful to improve communication with parents having vaccine concerns. Nurses have a crucial role in vaccine uptake and acceptance. Interventions aiming to strengthen their communication with parents are therefore essential, especially in areas with lower vaccine acceptance.

Design and implementation of tailored intervention to increase vaccine acceptance in a Somali community in Stockholm, Sweden - based on the Tailoring Immunization Programmes approach.

Objectives: Sweden has had a high and stable vaccination coverage for measles-mumps-rubella (MMR) vaccine (>96%) through the national immunization program (NIP), but coverage rates highlight local pockets of lower vaccination coverage. This project addressed low MMR vaccine acceptance among parents in a Somali community, in Stockholm. The objective of the intervention was to increase vaccine confidence and MMR-vaccine uptake and also to inform practices addressing vaccine acceptance. Study design: This paper describes the design and implementation of a multi-component intervention based on the Tailoring Immunization Programmes (TIP) approach, developed by the WHO European Regional Office. Methods: The theoretical underpinning of TIP is the Capability, Opportunity, and Motivation Model (COM-B model) and Behaviour Change Wheel framework (BCW), adapted for vaccination. The COM-model was used to identify barriers and drivers to vaccination and intervention types. The TIP-phases described in this paper are: pre-TIP (planning), three succeeding TIP phases (situational analysis, formative research, intervention design) and the post-TIP phase (implementation). Results: The situation analysis and formative research revealed that parents feared the MMR vaccine due to autism or that their child would stop talking following vaccination, despite lack of scientific evidence for an association between autism and MMR vaccines. Barriers were linked to their associated COM-B factors and mapped to appropriate intervention types for two target groups: Somali parents and nurses at the Child Health Centres (CHC). Selected intervention types targeting parents were education, persuasion and modelling whereas education and training were selected for CHC nurses. The intervention activities included community engagement for parents, while the activities for nurses focused on improving encounters and dialogue with parents having low vaccine acceptance. Following the intervention design the activities were developed, pilot tested and implemented. Conclusion: This study confirm that the TIP approach is valuable for guiding a stepwise working process for a thorough understanding of barriers and drivers for MMR vaccination among parents in this Somali community. It facilitated the design of a theory and evidence-informed intervention targeting parents and nurses.

Behavioural insights and the evolving COVID-19 pandemic.

Behavioural sciences have complemented medical and epidemiological sciences in the response to the SARS-CoV-2 pandemic. As vaccination uptake continues to increase across the EU/EEA - including booster vaccinations - behavioural science research remains important for both pandemic policy, planning of services and communication. From a behavioural perspective, the following three areas are key as the pandemic progresses: (i) attaining and maintaining high levels of vaccination including booster doses across all groups in society, including socially vulnerable populations, (ii) informing sustainable pandemic policies and ensuring adherence to basic prevention measures to protect the most vulnerable population, and (iii) facilitating population preparedness and willingness to support and adhere to the reimposition of restrictions locally or regionally whenever outbreaks may occur. Based on mixed-methods research, expert consultations, and engagement with communities, behavioural data and interventions can thus be important to prevent and effectively respond to local or regional outbreaks, and to minimise socioeconomic and health disparities. In this Perspective, we briefly outline these topics from a European viewpoint, while recognising the importance of considering the specific context in individual countries.

HIV-DNA Given with or without Intradermal Electroporation Is Safe and Highly Immunogenic in Healthy Swedish HIV-1 DNA/MVA Vaccinees: A Phase I Randomized Trial.

BACKGROUND: We compared safety and immunogenicity of intradermal (ID) vaccination with and without electroporation (EP) in a phase I randomized placebo-controlled trial of an HIV-DNA prime HIV-MVA boost vaccine in healthy Swedish volunteers. METHODS: HIV-DNA plasmids encoding HIV-1 genes gp160 subtypes A, B and C; Rev B; Gag A and B and RTmut B were given ID at weeks 0, 6 and 12 in a dose of 0.6 mg. Twenty-five volunteers received vaccine using a needle-free device (ZetaJet) with (n=16) or without (n=9) ID EP (Dermavax). Five volunteers were placebo recipients. Boosting with recombinant MVA-CMDR expressing HIV-1 Env, Gag, Pol of CRF01_AE (HIV-MVA) or placebo was performed at weeks 24 and 40. Nine of the vaccinees received a subtype C CN54 gp140 protein boost together with HIV-MVA. RESULTS: The ID/EP delivery was very well tolerated. After three HIV-DNA immunizations, no statistically significant difference was seen in the IFN-γ ELISpot response rate to Gag between HIV-DNA ID/EP recipients (5/15, 33%) and HIV-DNA ID recipients (1/7, 14%, p=0.6158). The first HIV-MVA or HIV-MVA+gp140 vaccination increased the IFN-γ ELISpot response rate to 18/19 (95%). CD4+ and/or CD8+ T cell responses to Gag or Env were demonstrable in 94% of vaccinees. A balanced CD4+ and CD8+ T cell response was noted, with 78% and 71% responders, respectively. IFN-γ and IL-2 dominated the CD4+ T cell response to Gag and Env. The CD8+ response to Gag was broader with expression of IFN-γ, IL-2, MIP-1ß and/or CD107. No differences were seen between DNA vaccine groups. Binding antibodies were induced after the second HIV-MVA+/-gp140 in 93% of vaccinees to subtype C Env, with the highest titers among EP/gp140 recipients. CONCLUSION: Intradermal electroporation of HIV-DNA was well tolerated. Strong cell- and antibody-mediated immune responses were elicited by the HIV-DNA prime and HIV-MVA boosting regimen, with or without intradermal electroporation use. TRIAL REGISTRATION: International Standard Randomised Controlled Trial Number (ISRCTN) 60284968.

Priming with a simplified intradermal HIV-1 DNA vaccine regimen followed by boosting with recombinant HIV-1 MVA vaccine is safe and immunogenic: a phase IIa randomized clinical trial.

BACKGROUND: Intradermal priming with HIV-1 DNA plasmids followed by HIV-1MVA boosting induces strong and broad cellular and humoral immune responses. In our previous HIVIS-03 trial, we used 5 injections with 2 pools of HIV-DNA at separate sites for each priming immunization. The present study explores whether HIV-DNA priming can be simplified by reducing the number of DNA injections and administration of combined versus separated plasmid pools. METHODS: In this phase IIa, randomized trial, priming was performed using 5 injections of HIV-DNA, 1000 µg total dose, (3 Env and 2 Gag encoding plasmids) compared to two "simplified" regimens of 2 injections of HIV-DNA, 600 µg total dose, of Env- and Gag-encoding plasmid pools with each pool either administered separately or combined. HIV-DNA immunizations were given intradermally at weeks 0, 4, and 12. Boosting was performed intramuscularly with 108 pfu HIV-MVA at weeks 30 and 46. RESULTS: 129 healthy Tanzanian participants were enrolled. There were no differences in adverse events between the groups. The proportion of IFN-γ ELISpot responders to Gag and/or Env peptides after the second HIV-MVA boost did not differ significantly between the groups primed with 2 injections of combined HIV-DNA pools, 2 injections with separated pools, and 5 injections with separated pools (90%, 97% and 97%). There were no significant differences in the magnitude of Gag and/or Env IFN-γ ELISpot responses, in CD4+ and CD8+ T cell responses measured as IFN-γ/IL-2 production by intracellular cytokine staining (ICS) or in response rates and median titers for binding antibodies to Env gp160 between study groups. CONCLUSIONS: A simplified intradermal vaccination regimen with 2 injections of a total of 600 µg with combined HIV-DNA plasmids primed cellular responses as efficiently as the standard regimen of 5 injections of a total of 1000 µg with separated plasmid pools after boosting twice with HIV-MVA. TRIAL REGISTRATION: World Health Organization International Clinical Trials Registry Platform PACTR2010050002122368.

Broad and potent cellular and humoral immune responses after a second late HIV-modified vaccinia virus ankara vaccination in HIV-DNA-primed and HIV-modified vaccinia virus Ankara-boosted Swedish vaccinees.

We have previously shown that an HIV vaccine regimen including three HIV-DNA immunizations and a single HIV-modified vaccinia virus Ankara (MVA) boost was safe and highly immunogenic in Swedish volunteers. A median 38 months after the first HIV-MVA vaccination, 24 volunteers received 10(8) plaque-forming units of HIV-MVA. The vaccine was well tolerated. Two weeks after this HIV-MVA vaccination, 18 (82%) of 22 evaluable vaccinees were interferon (IFN)-γ enzyme-linked immunospot (ELISpot) reactive: 18 to Gag and 10 (45%) to Env. A median minimal epitope count of 4 to Gag or Env was found in a subset of 10 vaccinees. Intracellular cytokine staining revealed CD4(+) and/or CD8(+) T cell responses in 23 (95%) of 24 vaccinees, 19 to Gag and 19 to Env. The frequency of HIV-specific CD4(+) and CD8(+) T cell responses was equally high (75%). A high proportion of CD4(+) and CD8(+) T cell responses to Gag was polyfunctional with production of three or more cytokines (40% and 60%, respectively). Of the Env-specific CD4(+) T cells 40% were polyfunctional. Strong lymphoproliferative responses to Aldrithiol-2 (AT-2)-treated subtype A, B, C, and A_E virus were demonstrable in 21 (95%) of 22 vaccinees. All vaccinees developed binding antibodies to Env and Gag. Neutralizing antibodies were detected in a peripheral blood mononuclear cell (PBMC)-based assay against subtype B and CRF01_AE viruses. The neutralizing antibody response rates were influenced by the vaccine dose and/or mode of delivery used at the previous HIV-MVA vaccination. Thus, a second late HIV-MVA boost induced strong and broad cellular immune responses and improved antibody responses. The data support further exploration of this vaccine concept.

Broad and potent immune responses to a low dose intradermal HIV-1 DNA boosted with HIV-1 recombinant MVA among healthy adults in Tanzania.

BACKGROUND: We conducted a phase I/II randomized placebo-controlled trial with the aim of exploring whether priming with a low intradermal dose of a multiclade, multigene HIV-1 DNA vaccine could improve the immunogenicity of the same vaccine given intramuscularly prior to boosting with a heterologous HIV-1 MVA among healthy adults in Dar es Salaam, Tanzania. METHODS: Sixty HIV-uninfected volunteers were randomized to receive DNA plasmid vaccine 1mg intradermally (id), n=20, or 3.8mg intramuscularly (im), n=20, or placebo, n=20, using a needle-free injection device. DNA plasmids encoding HIV-1 genes gp160 subtype A, B, C; rev B; p17/p24 gag A, B and Rtmut B were given at weeks 0, 4 and 12. Recombinant MVA (10(8)pfu) expressing HIV-1 Env, Gag, Pol of CRF01_AE or placebo was administered im at month 9 and 21. RESULTS: The vaccines were well tolerated. Two weeks after the third HIV-DNA injection, 22/38 (58%) vaccinees had IFN-γ ELISpot responses to Gag. Two weeks after the first HIV-MVA boost all 35 (100%) vaccinees responded to Gag and 31 (89%) to Env. Two to four weeks after the second HIV-MVA boost, 28/29 (97%) vaccinees had IFN-γ ELISpot responses, 27 (93%) to Gag and 23 (79%) to Env. The id-primed recipients had significantly higher responses to Env than im recipients. Intracellular cytokine staining for Gag-specific IFN-γ/IL-2 production showed both CD8(+) and CD4(+) T cell responses. All vaccinees had HIV-specific lymphoproliferative responses. All vaccinees reacted in diagnostic HIV serological tests and 26/29 (90%) had antibodies against gp160 after the second HIV-MVA boost. Furthermore, while all of 29 vaccinee sera were negative for neutralizing antibodies against clade B, C and CRF01_AE pseudoviruses in the TZM-bl neutralization assay, in a PBMC assay, the response rate ranged from 31% to 83% positives, depending upon the clade B or CRF01_AE virus tested. CONCLUSIONS: This vaccine approach is safe and highly immunogenic. Low dose, id HIV-DNA priming elicited higher and broader cell-mediated immune responses to Env after HIV-MVA boost compared to a higher HIV-DNA priming dose given im. Three HIV-DNA priming immunizations followed by two HIV-MVA boosts efficiently induced Env-antibody responses.

Strong HIV-specific CD4+ and CD8+ T-lymphocyte proliferative responses in healthy individuals immunized with an HIV-1 DNA vaccine and boosted with recombinant modified vaccinia virus ankara expressing HIV-1 genes.

We investigated HIV-1 vaccine-induced lymphoproliferative responses in healthy volunteers immunized intradermally or intramuscularly (with or without adjuvant granulocyte-macrophage colony-stimulating factor [GM-CSF] protein) with DNA expressing HIV-1 gag, env, rev, and rt at months 0, 1, and 3 using a Biojector and boosted at 9 months with modified vaccinia virus Ankara (MVA) expressing heterologous HIV-1 gag, env, and pol (HIV-MVA). Lymphoproliferative responses to aldrithiol-2 (AT-2)-inactivated-HIV-1 antigen were tested by a [(3)H]thymidine uptake assay and a flow-cytometric assay of specific cell-mediated immune response in activated whole blood (FASCIA-WB) 2 weeks after the HIV-MVA boost (n = 38). A FASCIA using peripheral blood mononuclear cells (FASCIA-PBMC) was also employed (n = 14). Thirty-five of 38 (92%) vaccinees were reactive by the [(3)H]thymidine uptake assay. Thirty-two of 38 (84%) vaccinees were reactive by the CD4(+) T-cell FASCIA-WB, and 7 of 38 (18%) also exhibited CD8(+) T-cell responses. There was strong correlation between the proliferative responses measured by the [(3)H]thymidine uptake assay and CD4(+) T-cell FASCIA-WB (r = 0.68; P < 0.01). Fourteen vaccinees were analyzed using all three assays. Ten of 14 (71%) and 11/14 (79%) demonstrated CD4(+) T-cell responses in FASCIA-WB and FASCIA-PBMC, respectively. CD8(+) T-cell reactivity was observed in 3/14 (21%) and 7/14 (50%) using the FASCIA-WB and FASCIA-PBMC, respectively. All 14 were reactive by the [(3)H]thymidine uptake assay. The overall HIV-specific T-cell proliferative response in the vaccinees employing any of the assays was 100% (38/38). A standardized FASCIA-PBMC, which allows simultaneous phenotyping, may be an option to the [(3)H]thymidine uptake assay for assessment of vaccine-induced T-cell proliferation, especially in isotope-restricted settings.

A novel assay for assessment of HIV-specific cytotoxicity by multiparameter flow cytometry.

BACKGROUND: Assessment of CD8(+) T-cell activity is of significant importance for the evaluation of cellular immune responses to viral infections, especially in HIV. We present a new assay for the assessment of HIV-specific cytotoxicity by multiparameter flow cytometry. METHODS: Target cells, pulsed with peptide pools (Gag or Nef), were stained with 5- (and -6)-carboxyfluorescein diacetate succinimidyl ester (CFSE), cultured with specific or nonspecific effector cells, and finally stained with propidium iodide (PI). Determination of cytolysis is based on the enumeration of viable target cells (CFSE(hi)PI(-)) in the test sample (target and specific effector cells) as compared with that of the viable target cells in the control sample (target and nonspecific effector cells). The (51)Cr-release assay and IFN-gamma ELISpot were performed by standard procedures. RESULTS: A comparison with the Cr-release showed that the two assays were strongly correlated (r = 0.67; P < 0.001) but the sensitivity of the flow cytometric assay was significantly higher (P < 0.05), and the reproducibility good (CV, 7.7%). Good correlation was also found with the ELISpot assay (r = 0.66; P < 0.01). CONCLUSION: This new assay provides both specific and sensitive results when employed for the detection of HIV-specific CTL and can be a valuable tool for the evaluation of cytolytic activity in vaccine trials or in HIV-infected subjects, especially if such responses are present at low levels.

Optimum culture conditions for specific and nonspecific activation of whole blood and PBMC for intracellular cytokine assessment by flow cytometry.

The assessment of cytokine production is an important component of studies of cell-mediated immune responses (CMI) to immunological challenges. In this study, we present a method to enhance the detection of cytokine-producing cells by allowing antigen-specific cells to expand in long-term culture. We investigated the influence of the degree of dilution of whole blood and the duration of the incubation period on whole blood as well as peripheral blood mononuclear cells (PBMCs), cultured in the absence or presence of mitogens, superantigens or specific antigens, for intracellular cytokine production (IFNgamma, TNFalpha, IL-2, IL-4, IL-10 and IL-13) by CD4+ and CD8+ T lymphocytes using four-colour flow cytometry. Whole blood was diluted 1/1, 1/2, 1/5 and 1/10, and cultured for 6, 24, 48, 72 and 120 h in the presence of antibodies against the co-stimulatory molecules CD28 and CD49d, and, during the last 4 h of culture, in the presence of brefeldin A. Optimum conditions for detection of a high number of IFNgamma-positive cells were observed after 72 h of culture in blood diluted 1/10. Median frequencies of IFNgamma+ cells obtained after activation by PMA-ionomycin, PHA or SEA-B were 29.3%, 20.0% and 6.8% for CD4+ cells, and 67.8%, 20.6% and 6.8% for CD8+ cells. In blood samples diluted 1/5 or 1/10, and cultured in the presence of cytomegalovirus (CMV) or varicella-zoster virus (VZV), mean peak levels of 2.8% and 1.4% IFNgamma+CD4+ cells were recorded at 120 h. The levels of cells producing cytokines other than IFNgamma were generally much lower and, in the case of IL-4 and IL-13, difficult to distinguish from background levels recorded in cultures with medium only. Kinetic studies of cytokine production by PBMCs showed a pattern similar to that of whole blood with peak levels of IFNgamma-producing cells recorded at 72 h. The increased levels of IFNgamma production after culture for 72 h were due to an expansion of the numbers of cytokine-producing cells responsive to a specific stimulus. Antigen-specific cells are usually present only at low levels in peripheral blood and may not be detected following simple activation for a few hours. To reach a level of detection in such cases, culture of diluted blood for several days is recommended.