Antibodies Induced by Smallpox Vaccination after at Least 45 Years Cross-React with and In Vitro Neutralize Mpox Virus: A Role for Polyclonal B Cell Activation?

AIMS: To evaluate whether antibodies specific for the vaccinia virus (VV) are still detectable after at least 45 years from immunization. To confirm that VV-specific antibodies are endowed with the capacity to neutralize Mpox virus (MPXV) in vitro. To test a possible role of polyclonal non-specific activation in the maintenance of immunologic memory. METHODS: Sera were collected from the following groups: smallpox-vaccinated individuals with or without latent tuberculosis infection (LTBI), unvaccinated donors, and convalescent individuals after MPXV infection. Supernatant of VV- or MPXV-infected Vero cells were inactivated and used as antigens in ELISA or in Western blot (WB) analyses. An MPXV plaque reduction neutralization test (PRNT) was optimized and performed on study samples. VV- and PPD-specific memory T cells were measured by flow cytometry. RESULTS: None of the smallpox unvaccinated donors tested positive in ELISA or WB analysis and their sera were unable to neutralize MPXV in vitro. Sera from all the individuals convalescing from an MPXV infection tested positive for anti-VV or MPXV IgG with high titers and showed MPXV in vitro neutralization capacity. Sera from most of the vaccinated individuals showed IgG anti-VV and anti-MPXV at high titers. WB analyses showed that positive sera from vaccinated or convalescent individuals recognized both VV and MPXV antigens. Higher VV-specific IgG titer and specific T cells were observed in LTBI individuals. CONCLUSIONS: ELISA and WB performed using supernatant of VV- or MPXV-infected cells are suitable to identify individuals vaccinated against smallpox at more than 45 years from immunization and individuals convalescing from a recent MPXV infection. ELISA and WB results show a good correlation with PRNT. Data confirm that a smallpox vaccination induces a long-lasting memory in terms of specific IgG and that antibodies raised against VV may neutralize MPXV in vitro. Finally, higher titers of VV-specific antibodies and higher frequency of VV-specific memory T cells in LTBI individuals suggest a role of polyclonal non-specific activation in the maintenance of immunologic memory.

Validity, reliability, and cross-validation of a new questionnaire developed using the Theory of Planned Behavior: The Dating Violence Bystander Help-giving Intention Questionnaire (DVBHIQ).

The present study aimed to develop and psychometrically test a scale by using the Theory of Planned Behavior (TPB) comprising two types of measurement (direct and belief-based [indirect]) to assess bystander help-giving intention to victims of dating violence among youth. A two-phase, mixed-method design was adopted. The primary source of the samples was five universities, each in the northern, central, southern, eastern, and outer islands regions of Taiwan. Phase I involved developing an instrument based on the TPB (n = 10) and pilot testing (n = 220). Phase II conducted the psychometric evaluation (n = 622). The study used item analysis, explanatory factor analysis, confirmatory factor analysis, internal consistency, and cross-validation to examine the psychometric properties of the Dating Violence Bystander Help-giving Intention Questionnaire (DVBHIQ) with two types of measure (direct and belief-based). Explanatory factor analysis resulted in a four-factor solution (attitude/behavioral beliefs, subjective norms/normative beliefs, perceived behavioral control/control belief, and intention) of the direct and belief-based measures of the DVBHIQ, accounting for 72.67% and 76.62% of total variance respectively. Confirmatory factor analysis and cross-validation confirmed the proposed four-factor model and demonstrated good internal consistency reliability. The two types of DVBHIQ had good validity, reliability, and measurement invariance which may help address the core cognitive determinants for bystander help-giving intention. Healthcare providers (e.g., school nurses) could use the DVBHIQ to evaluate how bystander education programs affect youth and conduct related research in the future.

Public attitudes towards bystander CPR and their association with social deprivation: Findings from a cross sectional study in North England.

Background: Bystander cardiopulmonary resuscitation (BCPR) is undertaken in only 40% of out of hospital cardiac arrests (OHCAs) in the UK. Lower rates of BCPR and public access defibrillator (PAD) use have been correlated with lower socio-economic status (SES). The aim of this study was to examine knowledge and attitudes towards BCPR and PAD's using a study specific questionnaire, and to understand how these potentially interact with individual characteristics and SES. Methods: Cross-sectional study between July-December 2021 across areas of varying SES in North England. Results: Six hundred and one individuals completed the survey instrument (mean age = 51.9 years, 52.2 % female). Increased age was associated with being less willing to call 999 (p < 0.001) and follow call handler advice (p < 0.001). Female respondents were less comfortable performing BCPR than male respondents (p = 0.006). Individuals from least deprived areas were less likely to report comfort performing CPR, (p = 0.016) and less likely to know what a PAD is for, (p = 0.025). Higher education level was associated with increased ability to recognise OHCA (p = 0.005) and understanding of what a PAD is for (p < 0.001). Individuals with higher income were more likely to state they would follow advice regarding BCPR (p = 0.017) and report comfort using a PAD (p = 0.029). Conclusion: Individual characteristics such as age and ethnicity, rather than SES, are indicators of knowledge, willingness, and perceived competency to perform BCPR. Policy makers should avoid using SES alone to target interventions. Future research should examine how cultural identity and social cohesion intersect with these characteristics to influence willingness to perform BCPR.