Factors potentially contributing to the decline of the mpox outbreak in the Netherlands, 2022 and 2023.

BackgroundIn 2022 and 2023, a global outbreak of mpox affected mostly gay, bisexual and other men having sex with men (GBMSM). Outbreak control in the Netherlands included isolation, quarantine, post-exposure prophylaxis vaccination and primary preventive vaccination (PPV).AimWe describe the course of the outbreak, the vaccination programme, vaccine effectiveness (VE) of full vaccination against symptomatic disease, and trends in behaviour to generate hypotheses about factors that influenced the outbreak's decline.MethodsIn this observational study, we collected data from public health services on notified cases, number of PPV invitations and PPV doses administered. We calculated PPV uptake and coverage. Trends in behavioural data of GBMSM visiting sexual health centres were analysed for all consultations in 2022. We estimated VE using the screening method.ResultsUntil 31 December 2023, 1,294 mpox cases were reported. The outbreak peaked in early July 2022 and then declined sharply. PPV started on 25 July 2022; in total 29,851 doses were administered, 45.8% received at least one dose, 35.4% were fully vaccinated. The estimated VE was 68.2% (95% CI 4.3-89.5%). We did not observe an evident decrease in high-risk behaviour.DiscussionIt is unlikely that PPV was a driver of the outbreak's decline, as incidence started to decline well before the start of the PPV programme. The possible impact of behavioural change could not be demonstrated with the available indicators, however, the data had limitations, hampering interpretation. We hypothesise that infection-induced immunity in high-risk groups was an important factor explaining the decline.

Introducing video consultations at public sexual health clinics in the Netherlands: a mixed-methods study.

Video consultations (in combination with remote STI testing) can benefit both public sexual health clinics (SHCs) and their clients. The Dutch public SHCs explored the extent to which video consultations are accepted and appreciated-compared to face-to-face consultations-by both young clients (under 25 years) and nurses who normally carry out consultations. A mixed-methods study, using online questionnaires and telephone interviews with both young clients (aged under 25 years) and nurses (focus groups), was conducted to evaluate acceptance and appreciation of video and face-to-face consultations of the SHCs. Young clients evaluated 333 video consultations and 100 face-to-face consultations. Clients rated the VCs and F2F consultations as being of equal high level on five evaluation criteria (e.g. how it feels to talk about sex with a nurse, contact with the nurse). These positive results were confirmed in the interviews. Most important perceived advantages of VCs were time saving, ease, and feelings of comfort and safety. The nurses evaluated 422 VCs and 120 F2F consultations, rating the VCs and F2F consultations on an equal high level on three evaluation criteria (e.g., contact with the client, possibility to continue asking questions). Increasing accessibility of SHC consultations, getting faster to the point and saving time were mentioned as advantages of VCs during the focus group sessions with nurses. Video consultations are accepted and appreciated by young clients and nurses. They can be used for standard STI consultations that do not require a physical examination.

Traditionally, public health consultations for sexually transmitted infections (STIs) and other sexual health problems that young people in the Netherlands have, are offered on a face-to-face (F2F) basis. For some clients, who, for example, live further away from a clinic or are afraid of meeting acquaintances at the clinic, this can create barriers. By offering video consultations (VCs) these barriers can be removed. For clinics, VCs may cut costs and may reach high-risk clients via online services who do not make sufficient use of F2F consultations. Using a mixed-methods study, we investigated to what extent young clients and nurses accepted and rated VCs compared to face-to-face consultations. 433 young clients evaluated 333 VCs and 100 F2F consultations. Nurses evaluated 422 VCs and 120 F2F consultations. The young clients of Sexual Health Clinics (SHCs) appreciated and accepted a VC on a similar level to that of a F2F consultation. According to nurses, VCs can be an attractive addition to the services of SHCs. VCs can be used for standard STI consultations that do not require a physical examination. The advantages of VCs can contribute to reaching target groups that make less use of the current services of SHCs.

Where to go to in chlamydia control? From infection control towards infectious disease control.

OBJECTIVES: The clinical and public health relevance of widespread case finding by testing for asymptomatic chlamydia infections is under debate. We wanted to explore future directions for chlamydia control and generate insights that might guide for evidence-based strategies. In particular, we wanted to know the extent to which we should pursue testing for asymptomatic infections at both genital and extragenital sites. METHODS: We synthesised findings from published literature and from discussions among national and international chlamydia experts during an invitational workshop. We described changing perceptions in chlamydia control to inform the development of recommendations for future avenues for chlamydia control in the Netherlands. RESULTS: Despite implementing a range of interventions to control chlamydia, there is no practice-based evidence that population prevalence can be reduced by screening programmes or widespread opportunistic testing. There is limited evidence about the beneficial effect of testing on pelvic inflammatory disease prevention. The risk of tubal factor infertility resulting from chlamydia infection is low and evidence on the preventable fraction remains uncertain. Overdiagnosis and overtreatment with antibiotics for self-limiting and non-viable infections have contributed to antimicrobial resistance in other pathogens and may affect oral, anal and genital microbiota. These changing insights could affect the outcome of previous cost-effectiveness analysis. CONCLUSION: The balance between benefits and harms of widespread testing to detect asymptomatic chlamydia infections is changing. The opinion of our expert group deviates from the existing paradigm of 'test and treat' and suggests that future strategies should reduce, rather than expand, the role of widespread testing for asymptomatic chlamydia infections.

A survey-based assessment of rates and covariates of mpox diagnosis and vaccination provides evidence to refine eligibility criteria for mpox vaccination among gay, bisexual and other men who have sex with men in the Netherlands.

Background: The 2022 multicountry mpox outbreaks predominantly affected gay, bisexual and other men who have sex with men (GBMSM) in non-endemic countries, including in the Netherlands. We conducted a survey-based assessment of the alignment between the risk factors associated with mpox diagnosis among GBMSM in the Netherlands and the eligibility criteria used in 2022 for vaccinating this group, with the aim to refine these criteria. Methods: An online self-report survey was conducted among adult GBMSM in the Netherlands between 29 July and 30 August 2022, corresponding to the first month of the Dutch mpox vaccination campaign. GBMSM were recruited via advertisements on social media and gay dating apps. Participants reported on their sexual behaviour, mpox diagnosis, and/or (initial) mpox vaccination since the start of the outbreak. Covariables of mpox diagnosis and vaccination were assessed using logistic regression analyses. Results: Of the 2,460 participants, 73 (3.0%, 95% CI 2.3-3.6%) were diagnosed with mpox and 485 (19.7%, 95% CI 18.1-21.3%) had received (initial) mpox vaccination. Using sample weighting, we estimated that, of the GBMSM population aged 18-80 years in the Netherlands, 1.1% (95% CI 0.7-1.6%) had been diagnosed with mpox and 7.8% (95% CI 6.8-8.9%) had received (initial) vaccination. HIV-PrEP use, living with HIV, reporting ≥20 sex partners in the past 12 months, and sex in sex venues/parties in the past 2 months were independent risk factors for mpox diagnosis. Except for sex in sex venues/parties, these variables were also independently associated with mpox vaccination. Conclusion: This study provides novel evidence regarding the degree to which the 2022 eligibility criteria for mpox vaccination align with the risk factors for mpox among GBMSM in the Netherlands. The findings contribute to a refinement of the eligibility criteria for mpox vaccination, to which sex in sex venues/parties should be added.

An Implementation Pilot of Web-Based Self-Training Programs on Sexual Dysfunctions in the Dutch Public Sexual Health Setting: Mixed Methods Study.

BACKGROUND: Web-based sexual health interventions may be more acceptable to people compared with face-to-face support, given the stigma and embarrassment often associated with sexual problems. The Dutch public sexual health clinics (SHCs) conducted an implementation pilot with 4 web-based self-training programs on sexual dysfunctions (WSTPs) for young people. In addition to a basic sexuality program, the WSTPs focused on the following complaints: pain during intercourse, premature ejaculation, and no sex drive. OBJECTIVE: This study aims to gain insight into the potential reach of the freely offered WSTPs; use, acceptance, evaluation, and perceived impact of the WSTPs by young people; and evaluation and acceptance of the WSTPs by nurses of the SHCs. METHODS: A quantitative baseline measurement (BM) and a follow-up measurement (FM) were conducted among the users. In addition, qualitative data were gathered through video interviews with a sample of respondents of the FM and nurses of the SHCs to gain more in-depth insights into their assessment of the WSTPs. Participants were recruited via social media, posters, and referrals by nurses of the SHCs. Quantitative data were analyzed using descriptive statistics. Independent 2-tailed t tests and one-way independent ANOVAs were used to compare the scores between subgroups based on background characteristics. Dependent 2-tailed t tests were used to assess the possible changes between BM and FM. The interviews were analyzed using a thematic analysis. RESULTS: A total of 1028 young people (aged 16-24 y) completed the BM, 666 started with 1 of the WSTPs, and 104 participants completed the FM. In addition, 8 users and 8 nurses were interviewed. Of the participants who completed the BM, 87.74% (902/1028) experienced moderate (411/1028, 39.98%) to high (491/1028, 47.76%) severity of complaints, of which 20.43% (210/1028) had had them for >1 year and 27.82% (286/1028) even for ≥2 years, and 38.91% (400/1028) were dissatisfied with their sex lives. Only 8.75% (90/1028) had sought professional help in the past 2 years. At FM, users rated satisfaction with their sex life more positively than they did at BM, and they experienced less discomfort from their complaints. The overall rating was positive, with a mean report grade of 7.3 (SD 1.45; on a 10-point scale). Anonymity, clear information and explanation, and practical exercises are indicated as strengths of the WSTPs, leading to more understanding and normalization. Nurses appreciate the high quality of information and accessibility of the WSTPs. They consider them as a valuable addition to the consultation hours. CONCLUSIONS: WSTPs can reach a large number of young people with sexual problems who are less likely to seek professional help. This can result in an improved understanding of their issues, a decrease in complaints, and reduced barriers to communicating with a partner or professional.

[Increase in localised symptoms in 4-year-olds following revaccination with DaPT-IPV]. / Toename van lokale verschijnselen bij 4-jarigen na revaccinatie met DKTP.

OBJECTIVE: To present an inventory of notifications of serious local reactions after revaccination of 4-year-old children with DaPT-IPV (diphtheria vaccine, acellular pertussis vaccine, tetanus vaccine and poliomyelitis vaccine), who had been vaccinated as a toddler with whole-cell pertussis combination vaccine (DwPT-IPV-Hib) and/or (from 2005 onward) with the acellular pertussis combination vaccine (DaPT-IPV-Hib). DESIGN: Descriptive inventory METHOD: Via an enhanced passive surveillance system professionals and private individuals can report an adverse event following vaccination within the Dutch national vaccination programme. The number of notifications of local side effects was related to the total number of vaccinated children registered in Praeventis, a national vaccination register in which information on an individual level is available. RESULTS: In 2008, we received an increasing number of notifications of serious local reactions after the revaccination of 4-year-olds with acellular DPT-IPV (average 3 per 1000 vaccinated children) with a peak in October/November. These children had also been vaccinated with acellular pertussis vaccine as infants. The symptoms of swelling and redness of sometimes the entire upper arm arose mostly the day after the vaccination and disappeared within 4 to 5 days without sequelae. CONCLUSION: Although the mechanisms underlying these serious local reactions are still not well understood, they do not imply an acute allergic reaction or infection and so medication against such reactions is not usually necessary.

Reactogenicity of infant whole cell pertussis combination vaccine compared with acellular pertussis vaccines with or without simultaneous pneumococcal vaccine in the Netherlands.

BACKGROUND: In addition to the routine enhanced passive safety surveillance of the Dutch National Vaccination Programme, RIVM (National Institute for Public Health and the Environment) started a large questionnaire study enrolling approximately 53,000 children from December 2003 until September 2007. AIM: We intended to establish accurate frequency estimates for several more severe adverse events and to compare the incidence rates of three different infant vaccines that were used consecutively. METHODS: Whole cell pertussis (wP) DTP-IPV-Hib vaccine (NVI) was replaced by acellulair pertussis (aP) in 2005, first Infanrix-IPV-Hib (GSK) followed by Pediacel (Sanofi) in 2006. Pneumococcal vaccine, Prevenar (Wyeth), was added for children born from April 2006. RESULTS: Parents returned 28,796 questionnaires (response 54%), 15,069 for whole cell pertussis and 13,727 for acellular pertussis vaccine, including 4485 with pneumococcal vaccine. The OR for reported events was 3-6 for whole cell pertussis vaccine compared with acellular vaccine. This was true for prolonged crying for 3h and more after the first dose (1.5% versus 0.4%; 95 CI 1.1-1.9 and 95% CI 0.2-0.7, respectively), and very high fever of 40.5 degrees C and over following the fourth dose (0.8% versus 0.2%; 95% CI 0.5-1.1 and 0.06-0.3, respectively), while possible febrile convulsions were diagnosed only twice after the fourth dose in the whole cell vaccine group and one after acellular pertussis vaccine. Pallor was significantly more frequent after the first dose of whole cell pertussis than after acellulair pertussis vaccination (18.3% versus 3.4%; 95% CI 17.2-19.5 and 95% CI 2.8-4.0 respectively) Collapse after the first dose was rare in both vaccine groups (5 after whole cell vaccine and 1 after acellular vaccine). The addition of conjugated pneumococcal vaccine did not result in statistically significant increased rates of adverse events in the acellular vaccine group. CONCLUSION: Whole cell pertussis vaccine showed a significantly higher reactogenicity regarding the adverse events analysed, while addition of conjugated pneumococcal vaccine administered simultaneously with acellular pertussis showed no statistically different adverse event profile.

Performance of the Brighton collaboration case definition for hypotonic-hyporesponsive episode (HHE) on reported collapse reactions following infant vaccinations in the Netherlands.

We reviewed collapse (sudden onset of pallor, limpness and hyporesponsiveness) following the first infant (DPTP+Hib) vaccination reported to the enhanced passive surveillance system of the Netherlands in 1994-2003. All 1303 reports identified by the current RIVM (National Institute for Public Health and Environment) case definition were captured by the Brighton Collaboration (BC) case definition, with in 17 (1.3%) reports insufficient information. Over the years the proportion of the highest level of diagnostic certainty (level 1) increased due to more complete data from 70% to over 90%. We checked the BC case definition also on a sample of cases (with pallor or hyporesponsiveness) not meeting RIVM's case definition for collapse at the time. Sixty out of 200 cases were captured by BC but again rejected by RIVM. The sensitivity BC levels 2 and 3 appeared too high. We recommend a more restrict case definition by the Brighton Collaboration with certain exclusion criteria to make it more specific. Furthermore a change in the specifications for levels 2 and 3 will increase specificity and accommodate for the loss of sensitivity.

Efficacies of whole cell and acellular pertussis vaccines against Bordetella parapertussis in a mouse model.

Pertussis vaccine development has mainly focused on Bordetella pertussis, and consequently these vaccines contain B. pertussis antigens only. However, the related species Bordetella parapertussis can also cause pertussis, although symptoms associated with the disease are generally considered to be milder. Recent field studies have shown that in some outbreaks B. parapertussis can prevail. Using a mouse model we compared the efficacy against B. parapertussis of two commercially available acellular vaccines and two whole cell vaccines, used in The Netherlands and Finland, respectively. The efficacies of the two whole cell vaccines against B. parapertussis were similar, but much lower compared to the efficacy against B. pertussis. Although, the acellular vaccines conferred some protection against B. parapertussis early in infection, the values were not significant. Later in infection, a highly significant enhancement of colonisation by B. parapertussis was observed in mice vaccinated with acellular vaccines. The whole cell vaccines protected significantly better than the acellular vaccines against B. parapertussis. The possible consequences of a switch from whole cell to acellular vaccines was discussed in the light of our findings.