Exposure factors associated with SARS-CoV-2 seroprevalence during the first eight months of the COVID-19 pandemic in the Netherlands: A cross-sectional study

SARS-CoV-2 cellular and humoral responses in vaccine-naive individuals during the first two waves of COVID-19 infections in the southern region of The Netherlands: a cross-sectional population-based study

With the emergence of highly transmissible variants of concern, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) still poses a global threat of coronavirus disease 2019 (COVID-19) resurgence. Cellular responses to novel variants are more robustly maintained than humoral responses, and therefore, cellular responses are of interest in assessing immune protection against severe disease in the population. We aimed to assess cellular responses to SARS-CoV-2 at the population level. IFNγ (interferon γ) responses to wild-type SARS-CoV-2 were analyzed using an ELISpot assay in vaccine-naive individuals with different humoral responses: Ig (IgM and/or IgG) seronegative (n = 90) and seropositive (n = 181) with low (<300 U/mL) or high (≥300 U/mL) humoral responses to the spike receptor binding domain (anti-S-RBD). Among the seropositive participants, 71.3% (129/181) were IFNγ ELISpot positive, compared to 15.6% (14/90) among the seronegative participants. Common COVID-19 symptoms such as fever and ageusia were associated with IFNγ ELISpot positivity in seropositive participants, whereas no participant characteristics were associated with IFNγ ELISpot positivity in seronegative participants. Fever and/or dyspnea and anti-S-RBD levels were associated with higher IFNγ responses. Symptoms of more severe disease and higher anti-S-RBD responses were associated with higher IFNγ responses. A significant proportion (15.6%) of seronegative participants had a positive IFNγ ELISpot. Assessment of cellular responses may improve estimates of the immune response to SARS-CoV-2 in the general population.

IMPORTANCE

Data on adaptive cellular immunity are of interest to define immune protection against severe acute respiratory syndrome coronavirus 2 in a population, which is important for decision-making on booster-vaccination strategies. This study provides data on associations between participant characteristics and cellular immune responses in vaccine-naive individuals with different humoral responses.

The association between SARS-CoV-2 seroprevalence and cross-border mobility for visiting family or friends among Dutch residents of a Euregional province

BACKGROUND

Border measures were implemented in many countries as infection prevention measures to interrupt between-country COVID-19 transmission. Border closings impact border region residents, as their professional and social lives are often intertwined across national borders. We studied whether crossing borders to visit family/friends in neighbouring countries (cross-border mobility) was associated with SARS-CoV-2 seroprevalence in Dutch Euregional residents.

METHODS

SARS-CoV-2 serostatus (negative/positive) was assessed (pre-vaccination) using laboratory testing to determine previous infection. Visiting Belgian or German family/friends in February-March 2020 was questioned. The association between cross-border mobility and seroprevalence was tested using logistic regression analysis, adjusted for previously identified exposure factors.

RESULTS

In 9,996 participants, 36.8 % (n = 3,677) reported cross-border family/friends. Of these, one-third (n = 1,306) visited their cross-border family/friends in February-March 2020. Multivariable analyses revealed no positive association between cross-border mobility and seropositivity, for both participants living in a border municipality (ORfamily/friends not visited=0.90 [95 % CI:0.78-1.04], ORfamily/friends visited=0.88 [95 % CI:0.73-1.05]), and for participants not living in a border municipality (ORfamily/friends not visited=0.91 [95 % CI:0.72-1.16], ORfamily/friends visited=0.62 [95 % CI:0.41-0.94]).

CONCLUSIONS

This study provided no evidence of cross-border mobility as an important exposure factor for SARS-CoV-2. The results of our unique real-world study suggest that cross-border mobility did not substantially contribute to cross-border SARS-CoV-2 transmission in the Netherlands.

Perceived barriers and facilitators to infection prevention and control in Dutch residential care facilities for people with intellectual and developmental disabilities: a cross-sectional study

BACKGROUND

Adequate implementation of infection prevention and control (IPC) in residential care facilities (RCFs) for people with intellectual and developmental disabilities (IDDs) is crucial to safeguarding this vulnerable population. Studies in this field are scarce. This study aimed to identify perceived barriers to and facilitators of IPC among professionals working in these settings, along with recommendations to improve IPC, to inform the development of targeted interventions.

METHODS

We administered an online questionnaire to 319 professionals from 16 Dutch RCFs for people with IDDs (March 2021-March 2022). Perceived multilevel barriers and facilitators (guideline, client, interpersonal, organisational, care sector, and policy level) were measured on a 5-point Likert scale (totally disagree-totally agree). Recommendations were assessed using a 5-point Likert scale (not at all helpful-extremely helpful), supplemented by an open-ended question. Barriers, facilitators, and recommendations were analysed by descriptive statistics. Open answers to recommendations were analysed through thematic coding.

RESULTS

Barriers to IPC implementation included the client group (e.g., lack of hygiene awareness) (63%), competing values between IPC and the home-like environment (42%), high work pressure (39%), and the overwhelming quantity of IPC guidelines/protocols (33%). Facilitators included perceived social support on IPC between professionals and from supervisors (90% and 80%, respectively), procedural clarity of IPC guidelines/protocols (83%), and the sense of urgency for IPC in the organisation (74%). Main recommendations included the implementation of clear IPC policies and regulations (86%), the development of a practical IPC guideline (84%), and the introduction of structural IPC education and training programmes (for new staff members) (85%). Professionals also emphasised the need for IPC improvement efforts to be tailored to the local care context, and to involve clients and their relatives.

CONCLUSIONS

To improve IPC in disability care settings, multifaceted strategies should be adopted. Initial efforts should involve clients (and relatives), develop a practical and context-specific IPC guideline, encourage social support among colleagues through interprofessional coaching, reduce workload, and foster an IPC culture including shared responsibility within the organisation.

Social networks and health behaviors during the COVID-19 pandemic: a qualitative study among older adults in the Netherlands

Aim

Social networks, all social relationships that people have, may influence people's health behavior and well-being, which was evaluated in this qualitative study in older adults. Furthermore, we evaluated people's needs for strengthening social networks.

Subject and methods

For this qualitative study, semi-structured interviews were conducted between May and July 2021 among 24 adults aged 60 years and older.

Results

Respondents provided information on social network structure (number and types of relations) and function (social support). They received informational support from friends, emotional support from their partner/spouse, and all types of support (including practical support) from family. Respondents stated that their health behavior was mainly influenced by a partner/spouse. Family and friends were mostly for socializing. To strengthen networks, in-person bilateral or small group interactions were preferred.

Conclusion

Family and friends were important social supporters and positively influenced health behaviors. This study emphasizes the importance of social networks in health promotion.