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BackgroundVaccine uptake differs between social groups. Mobile vaccination units (MV-units) were deployed in the Netherlands by municipal health services in neighbourhoods with low uptake of COVID-19 vaccines.AimWe aimed to evaluate the impact of MV-units on vaccine uptake in neighbourhoods with low vaccine uptake.MethodsWe used the Dutch national-level registry of COVID-19 vaccinations (CIMS) and MV-unit deployment registrations containing observations in 253 neighbourhoods where MV-units were deployed and 890 contiguous neighbourhoods (total observations: 88,543 neighbourhood-days). A negative binomial regression with neighbourhood-specific temporal effects using splines was used to study the effect.ResultsDuring deployment, the increase in daily vaccination rate in targeted neighbourhoods ranged from a factor 2.0 (95% confidence interval (CI): 1.8-2.2) in urbanised neighbourhoods to 14.5 (95% CI: 11.6-18.0) in rural neighbourhoods. The effects were larger in neighbourhoods with more voters for the Dutch conservative Reformed Christian party but smaller in neighbourhoods with a higher proportion of people with non-western migration backgrounds. The absolute increase in uptake over the complete intervention period ranged from 0.22 percentage points (95% CI: 0.18-0.26) in the most urbanised neighbourhoods to 0.33 percentage point (95% CI: 0.28-0.37) in rural neighbourhoods.ConclusionDeployment of MV-units increased daily vaccination rate, particularly in rural neighbourhoods, with longer travel distance to permanent vaccination locations. This public health intervention shows promise to reduce geographic and social health inequalities, but more proactive and long-term deployment is required to identify its potential to substantially contribute to overall vaccination rates at country level.
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Vacunas contra la COVID-19 , COVID-19 , SARS-CoV-2 , Cobertura de Vacunación , Vacunación , Humanos , COVID-19/prevención & control , COVID-19/epidemiología , Países Bajos , Vacunas contra la COVID-19/administración & dosificación , Cobertura de Vacunación/estadística & datos numéricos , Vacunación/estadística & datos numéricos , Unidades Móviles de Salud/estadística & datos numéricos , Características de la Residencia/estadística & datos numéricos , Masculino , Femenino , Programas de Inmunización/estadística & datos numéricos , Adulto , Persona de Mediana Edad , Sistema de Registros , Población Rural/estadística & datos numéricosRESUMEN
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.
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Brotes de Enfermedades , Homosexualidad Masculina , Vacunación , Humanos , Países Bajos/epidemiología , Masculino , Homosexualidad Masculina/estadística & datos numéricos , Adulto , Vacunación/estadística & datos numéricos , Persona de Mediana Edad , Adulto Joven , Profilaxis Posexposición , Enfermedades de Transmisión Sexual/epidemiología , Enfermedades de Transmisión Sexual/prevención & control , Femenino , Minorías Sexuales y de Género/estadística & datos numéricos , Adolescente , Cuarentena , Programas de Inmunización , Conducta Sexual/estadística & datos numéricosRESUMEN
We present early vaccine effectiveness (VE) estimates of the 2023 seasonal COVID-19 XBB.1.5 vaccine against COVID-19 hospitalisation and admission to an intensive care unit (ICU) in previously vaccinated adults ≥ 60 years in the Netherlands. We compared vaccination status of 2,050 hospitalisations including 92 ICU admissions with age group-, sex-, region- and date-specific population vaccination coverage between 9 October and 5 December 2023. VE against hospitalisation was 70.7% (95%â¯CI: 66.6-74.3), VE against ICU admission was 73.3% (95%â¯CI: 42.2-87.6).
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COVID-19 , Vacunas , Adulto , Humanos , Vacunas contra la COVID-19 , Países Bajos/epidemiología , Eficacia de las Vacunas , COVID-19/prevención & control , Cuidados Críticos , HospitalizaciónAsunto(s)
Mpox , Eficacia de las Vacunas , Humanos , Mpox/prevención & control , Profilaxis PosexposiciónRESUMEN
BackgroundIn summer 2022, SARS-CoV-2 Omicron BA.5 became dominant in Europe. In vitro studies have shown a large reduction of antibody neutralisation for this variant.AimWe aimed to investigate differences in protection from previous infection and/or vaccination against infection with Omicron BA.4/5 vs BA.2.MethodsWe employed a case-only approach including positive PCR tests from community testing between 2 May and 24 July 2022 that were tested for S gene target failure (SGTF), which distinguishes BA.4/5 from BA.2 infection. Previous infections were categorised by variant using whole genome sequencing or SGTF. We estimated by logistic regression the association of SGTF with vaccination and/or previous infection, and of SGTF of the current infection with the variant of the previous infection, adjusting for testing week, age group and sex.ResultsThe percentage of registered previous SARS-CoV-2 infections was higher among 19,836 persons infected with Omicron BA.4/5 than among 7,052 persons infected with BA.2 (31.3% vs 20.0%). Adjusting for testing week, age group and sex, the adjusted odds ratio (aOR) was 1.4 (95%â¯CI: 1.3-1.5). The distribution of vaccination status did not differ for BA.4/5 vs BA.2 infections (aORâ¯=â¯1.1 for primary and booster vaccination). Among persons with a previous infection, those currently infected with BA4/5 had a shorter interval between infections, and the previous infection was more often caused by BA.1, compared with those currently infected with BA.2 (aORâ¯=â¯1.9; 95%â¯CI: 1.5-2.6).ConclusionOur results suggest immunity induced by BA.1 is less effective against BA.4/5 infection than against BA.2 infection.
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COVID-19 , Humanos , Países Bajos/epidemiología , COVID-19/epidemiología , SARS-CoV-2/genética , Europa (Continente) , Inmunización SecundariaRESUMEN
We used data of 32,542 prospective cohort study participants who previously received primary and one or two monovalent booster COVID-19 vaccinations. Between 26 September and 19 December 2022, relative effectiveness of bivalent original/Omicronâ¯BA.1 vaccination against self-reported Omicron SARS-CoV-2 infection was 31% in 18-59-year-olds and 14% in 60-85-year-olds. Protection of Omicron infection was higher than of bivalent vaccination without prior infection. Although bivalent booster vaccination increases protection against COVID-19 hospitalisations, we found limited added benefit in preventing SARS-CoV-2 infection.
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COVID-19 , Humanos , Países Bajos/epidemiología , COVID-19/prevención & control , Estudios Prospectivos , SARS-CoV-2/genética , ARN Mensajero , VacunaciónRESUMEN
BackgroundDifferential SARS-CoV-2 exposure between vaccinated and unvaccinated individuals may confound vaccine effectiveness (VE) estimates.AimWe conducted a test-negative case-control study to determine VE against SARS-CoV-2 infection and the presence of confounding by SARS-CoV-2 exposure.MethodsWe included adults tested for SARS-CoV-2 at community facilities between 4 July and 8 December 2021 (circulation period of the Delta variant). The VE against SARS-CoV-2 infection after primary vaccination with an mRNA (Comirnaty or Spikevax) or vector-based vaccine (Vaxzevria or Janssen) was calculated using logistic regression adjusting for age, sex and calendar week (Model 1). We additionally adjusted for comorbidity and education level (Model 2) and SARS-CoV-2 exposure (number of close contacts, visiting busy locations, household size, face mask wearing, contact with SARS-CoV-2 case; Model 3). We stratified by age, vaccine type and time since vaccination.ResultsVE against infection (Model 3) was 64% (95% CI: 50-73), only slightly lower than in Models 1 (68%; 95% CI: 58-76) and 2 (67%; 95% CI: 56-75). Estimates stratified by age group, vaccine and time since vaccination remained similar: mRNA VE (Model 3) among people ≥â¯50 years decreased significantly (p = 0.01) from 81% (95% CI: 66-91) at < 120 days to 61% (95% CI: 22-80) at ≥â¯120 days after vaccination. It decreased from 83% to 59% in Model 1 and from 81% to 56% in Model 2.ConclusionSARS-CoV-2 exposure did not majorly confound the estimated COVID-19 VE against infection, suggesting that VE can be estimated accurately using routinely collected data without exposure information.
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Vacunas contra la COVID-19 , COVID-19 , Adulto , Humanos , Persona de Mediana Edad , Países Bajos/epidemiología , COVID-19/epidemiología , COVID-19/prevención & control , Estudios de Casos y Controles , Eficacia de las Vacunas , SARS-CoV-2 , ARN MensajeroRESUMEN
We estimated SARS-CoV-2 vaccine effectiveness against onward transmission by comparing secondary attack rates among household members for vaccinated and unvaccinated index cases, based on source and contact tracing data collected when the Delta variant was dominant. Effectiveness of full vaccination of the index case against transmission to unvaccinated and fully vaccinated household contacts, respectively, was 63% (95% confidence interval (CI): 46-75) and 40% (95% CI: 20-54), in addition to the direct protection of vaccination of contacts against infection.
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COVID-19 , Vacunas , Vacunas contra la COVID-19 , Composición Familiar , Humanos , Países Bajos/epidemiología , SARS-CoV-2RESUMEN
Several studies report high effectiveness of COVID-19 vaccines against SARS-CoV-2 infection and severe disease, however an important knowledge gap is the vaccine effectiveness against transmission (VET). We present estimates of the VET to household and other close contacts in the Netherlands, from February to May 2021, using contact monitoring data. The secondary attack rate among household contacts was lower for fully vaccinated than unvaccinated index cases (11% vs 31%), with an adjusted VET of 71% (95% confidence interval: 63-77).
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COVID-19 , SARS-CoV-2 , Vacunas contra la COVID-19 , Composición Familiar , Humanos , Países Bajos/epidemiologíaRESUMEN
High coronavirus incidence has prompted the Netherlands to implement a second lockdown. To elucidate the epidemic's development preceding this second wave, we analysed weekly test positivity in public test locations by population subgroup between 1 June and 17 October 2020. Hospitality and public transport workers, driving instructors, hairdressers and aestheticians had higher test positivity compared with a reference group of individuals without a close-contact occupation. Workers in childcare, education and healthcare showed lower test positivity.
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Distribución por Edad , Prueba de COVID-19 , COVID-19/epidemiología , Control de Enfermedades Transmisibles/métodos , Ocupaciones/estadística & datos numéricos , Pandemias , SARS-CoV-2/aislamiento & purificación , Adolescente , Adulto , Anciano , COVID-19/diagnóstico , COVID-19/prevención & control , Niño , Preescolar , Trazado de Contacto , Femenino , Accesibilidad a los Servicios de Salud , Hospitalización/estadística & datos numéricos , Humanos , Incidencia , Lactante , Recién Nacido , Masculino , Tamizaje Masivo , Persona de Mediana Edad , Países Bajos/epidemiología , Exposición Profesional , Distanciamiento Físico , Cuarentena , Riesgo , Adulto JovenRESUMEN
We observed an increase in notifications of puerperal group A Streptococcus (GAS) infections in July and August 2018 throughout the Netherlands without evidence for common sources. General practitioners reported a simultaneous increase in impetigo. We hypothesised that the outbreak of puerperal GAS infections resulted from increased exposure via impetigo in the community.We conducted a case-control study to assess peripartum exposure to possible, non-invasive GAS infections using an online questionnaire. Confirmed cases were recruited through public health services while probable cases and controls were recruited through social media. We calculated odds ratios (OR) and 95% confidence intervals (95% CI) with logistic regression analysis.We enrolled 22 confirmed and 23 probable cases, and 2,400 controls. Contact with persons with impetigo were reported by 8% of cases and 2% of controls (OR: 3.26, 95% CI: 0.98-10.88) and contact with possible GAS infections (impetigo, pharyngitis or scarlet fever) by 28% and 9%, respectively (OR: 4.12, 95% CI: 1.95-8.68). In multivariable analysis, contact with possible GAS infections remained an independent risk factor (aOR: 4.28, 95% CI: 2.02-9.09).We found an increased risk of puerperal fever after community contact with possible non-invasive GAS infections. Further study of this association is warranted.
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Brotes de Enfermedades/estadística & datos numéricos , Fiebre/etiología , Impétigo/microbiología , Faringitis/microbiología , Infección Puerperal/epidemiología , Escarlatina/microbiología , Infecciones Estreptocócicas/complicaciones , Streptococcus pyogenes/aislamiento & purificación , Adulto , Estudios de Casos y Controles , Notificación de Enfermedades , Transmisión de Enfermedad Infecciosa/estadística & datos numéricos , Femenino , Humanos , Impétigo/epidemiología , Países Bajos/epidemiología , Faringitis/epidemiología , Periodo Posparto , Embarazo , Infección Puerperal/microbiología , Escarlatina/epidemiología , Estaciones del Año , Infecciones Estreptocócicas/epidemiologíaRESUMEN
BACKGROUND: In 2016, an increase in invasive Haemophilus influenzae serotype b (Hib) disease was reported in the Netherlands in children younger than 5 years, which coincided with the introduction of the hexavalent diphtheria, tetanus, and acellular pertussis-hepatitis B virus-inactivated polio virus/Hib vaccine (DTPa-HBV-IPV/Hib) from 2011 onwards. We aimed to estimate the effectiveness of the hexavalent vaccine to assess whether this increase could be explained by decreasing effectiveness. METHODS: We did a case-control study in the Netherlands. We selected patients with a Hib infection (cases) by use of the surveillance records of the Netherlands Reference Laboratory for Bacterial Meningitis (Amsterdam). Cases with a Hib infection that began from Jan 1, 2003, to Dec 31, 2016, and who were younger than age 5 years were included. Ten controls from the national vaccination register (Praeventis) were selected for each case, matched by date of birth. Vaccination status was ascertained by use of Praeventis, which details the vaccination records of children living in the Netherlands. The last recorded vaccine dose was used to classify the child as having received the hexavalent DTPa-HBV-IPV/Hib vaccine or a pentavalent vaccine (which excludes the hepatitis B virus component) or another vaccine. We estimated the effectiveness of these vaccines by use of conditional logistic regression. FINDINGS: We included 159 (94%) of 170 cases reported and 1590 matched controls, who had a median age of 1·5 years (IQR 0·8-2·9). The remaining 11 cases could not be cross-matched with vaccination records from Praeventis. 91 (57%) of 159 cases had been vaccinated, compared with 1408 (89%) of 1590 controls. The overall vaccine effectiveness was 92·8% (95% CI 88·7-95·4), with no differences between the year of disease onset (p=0·9670). There were no differences conferred by type of vaccine given: vaccine effectiveness of the pentavalent and other vaccines was 91·8% (95% CI 86·1-95·1) versus 94·0% (89·0-96·8) for the hexavalent vaccine (OR 0·72, 95% CI 0·36-1·45; p=0·3591). Vaccine effectiveness was highest in children aged 1-2 years at disease onset (97·1-99·0%) and was lowest in children aged 3-4 years at disease onset (60·7-82·3%; p=0·0008). INTERPRETATION: Our results support the current vaccination programme, since Hib vaccine effectiveness has not decreased over time or by the introduction of the hexavalent DTPa-HBV-IPV/Hib vaccine. Vaccine effectiveness was high but waned with age. Alternative explanations for the increase in Hib disease therefore need to be assessed. FUNDING: Dutch Ministry of Health, Welfare and Sports.