BACKGROUND: Monitoring effectiveness of pertussis vaccines is necessary to adapt vaccination strategies. PERTINENT, Pertussis in Infants European Network, is an active sentinel surveillance system implemented in 35 hospitals across six EU/EEA countries. We aim to measure pertussis vaccines effectiveness (VE) by dose against hospitalisation in infants aged <1 year. METHODS: From December 2015 to December 2019, participating hospitals recruited all infants with pertussis-like symptoms. Cases were vaccine-eligible infants testing positive for Bordetella pertussis by PCR or culture; controls were those testing negative to all Bordetella spp. For each vaccine dose, we defined an infant as vaccinated if she/he received the corresponding dose >14 days before symptoms. Unvaccinated were those who did not receive any dose. We calculated (one-stage model) pooled VE as 100*(1-odds ratio of vaccination) adjusted for country, onset date (in 3-month categories) and age-group (when sample allowed it). RESULTS: Of 1,393 infants eligible for vaccination, we included 259 cases and 746 controls. Median age was 16 weeks for cases and 19 weeks for controls (p < 0.001). Median birth weight and gestational age were 3,235 g and week 39 for cases, 3,113 g and week 39 for controls. Among cases, 119 (46 %) were vaccinated: 74 with one dose, 37 two doses, 8 three doses. Among controls, 469 (63 %) were vaccinated: 233 with one dose, 206 two doses, 30 three doses. Adjusted VE after at least one dose was 59 % (95 %CI: 36-73). Adjusted VE was 48 % (95 %CI: 5-71) for dose one (416 eligible infants) and 76 % (95 %CI: 43-90) for dose two (258 eligible infants). Only 42 infants were eligible for the third dose. CONCLUSIONS: Our results suggest moderate one-dose and two-dose VE in infants. Larger sample size would allow more precise estimates for dose one, two and three.

• Keywords
• Hospital surveillance, Pertussis, Pertussis vaccine, Vaccine effectiveness, Whooping cough,
• MeSH
• Hospitalization MeSH
• Infant MeSH
• Humans MeSH
• Whooping Cough * epidemiology   prevention & control   MeSH
• Pertussis Vaccine MeSH
• Sentinel Surveillance MeSH
• Case-Control Studies MeSH
• Vaccination methods   MeSH
• Check Tag
• Infant MeSH
• Humans MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Pertussis Vaccine MeSH

INTRODUCTION: The completeness and timeliness of the pertussis questionnaire-based enhanced surveillance system (ESS) among infants and reported pertussis data within the electronic nationwide notification system (NNS) in the years 2015, 2017 and 2019 were evaluated in a pilot study. METHODS: The completeness of the variables for demographic characteristics, date of symptom onset, hospitalisation and vaccination status were assessed in both systems. Timeliness of reporting in the NNS was analysed as the interval between symptom onset and a) the date of first specimen collection (diagnostic delay), and b) the date of the Regional Public Health Authority receiving notification (notification delay). RESULTS: A total of 121 confirmed pertussis cases were reported to the NNS in the study years, while in the ESS a total of 104 confirmed cases were reported in infants. In both systems most cases were in the age group of one completed month of life (20% versus 23%) and males (55% versus 55%). The majority of cases were hospitalised (81% versus 85%) and unvaccinated (77% versus 78%). Within the NNS, the first dose of vaccine was reported in 13 cases, the second dose in 11, and third dose in three cases. Within the NNS, 100% completeness of following variables was found: symptom onset, week and region of reporting, age, gender and place of isolation. Median diagnostic delay was nine days. Median notification delay was 18 days. CONCLUSIONS: Data completeness was high in the NNS, except for lack of vaccination data in those eligible by age. Efforts to improve the completeness of laboratory-related variables and timeliness are essential. Based on the study results, the project of improving the ESS for infants will continue with regular evaluation.

UVOD: V pilotni študiji sta bili ovrednoteni popolnost in pravočasnost izboljšanega sistema za spremljanje (ESS) oslovskega kašlja pri dojenčkih, ki temelji na vprašalnikih, ter podatkov o oslovskem kašlju, vnesenih v elektronski sistem obveščanja na državni ravni (NNS), v letih 2015, 2017 in 2019. METODE: Pri obeh sistemih je bila ocenjena popolnost spremenljivk za demografske značilnosti, datum pojava simptomov ter hospitalizacijo in stanje cepljenja. Pravočasnost poročanja v sistem NNS je bila analizirana kot interval med pojavom simptomov in a) datumom prvega odvzema vzorcev (diagnostična zamuda); b) datumom, ko je regionalni organ za javno zdravje prejel informacije (zamuda pri obveščanju). REZULTATI: V obravnavanih letih je bilo v sistem NNS vnesenih 121 potrjenih primerov oslovskega kašlja, v sistemu ESS pa 104 potrjenih primerov pri dojenčkih. V obeh sistemih: večina primerov je bila v starostni skupini dopolnjenega 1 meseca (20 % v primerjavi s 23 %) in moškega spola (55 % v primerjavi 55 %). Večina primerov je bila hospitaliziranih (81 % v primerjavi s 85 %) in necepljenih (77 % v primerjavi z 78 %). V sistemu NNS je bila prva doza cepiva vnesena pri 13 primerih, druga doza pri 11 primerih in tretja doza pri 3 primerih. V sistemu NSN je bila ugotovljena 100-odstotna popolnost naslednjih spremenljivk: pojav simptomov, teden in regija poročanja, starost, spol in mesto izolacije. Povprečna diagnostična zamuda je bila 9 dni. Povprečna zamuda pri obveščanju je bila 18 dni. ZAKLJUČKI: Popolnost podatkov v sistemu NNS je bila na visoki ravni, razen pomanjkanja podatkov o cepljenju za primerne starosti. Treba si je prizadevati za izboljšanje popolnosti spremenljivk, povezanih z laboratoriji, in pravočasnosti. Na podlagi rezultatov študije se bo projekt izboljšanega sistema ESS pri dojenčkih nadaljeval z rednimi vrednotenji.

• Keywords
• Completeness, Infants, Pertussis, Surveillance, Timeliness, Whooping cough,
• Publication type
• Journal Article MeSH

BACKGROUND: PERTINENT is an active hospital-based surveillance system for pertussis in infants. In 2019, four of the six participating European countries recommended pertussis vaccination in pregnancy. Among infants aged <2 months, we measured the vaccine effectiveness (VE) in pregnancy; among infants aged 2-11 months, VE of vaccination in pregnancy and of primary vaccination (PV). METHODS: From December 2015 to 2019, we included all infants aged <1 year presenting with pertussis-like symptoms. Using a test-negative-design, cases were infants testing positive for Bordetella pertussis by PCR or culture. Controls were those testing negative for all Bordetella species. Vaccinated mothers were those who received vaccine in pregnancy. Vaccinated infants were those who received ≥1 dose of PV > 14 days before symptom onset. We excluded infants with unknown maternal or PV status or with mothers vaccinated ≤14 days before delivery. We calculated pooled VE as 100 * (1-odds ratio of vaccination) adjusted for study site, onset date in quarters and infants' age group. RESULTS: Of 829 infants presenting with pertussis-like symptoms, 336 (41%) were too young for PV. For the VE in pregnancy analysis, we included 75 cases and 201 controls. Vaccination in pregnancy was recorded for 9 cases (12%) and 92 controls (46%), adjusted VE was between 75% [95%CI: 35-91%] and 88% [95%CI: 57-96%]. Of 493 infants eligible for PV, we included 123 cases and 253 controls. Thirty-one cases and 98 controls recorded both PV with ≥ 1 dose and vaccination in pregnancy, adjusted VE was between 74% [95%CI: 33-90] and 95% [95%CI: 69-99]; 27 cases and 53 controls recorded PV only, adjusted VE was between 68% [95%CI: 27-86] and 94% [95%CI: 59-99]. CONCLUSION: Our findings suggest that vaccination in pregnancy reduces pertussis incidence in infants too young for PV. In infants aged 2-11 months, PV only and both PV and vaccination in pregnancy provide significant protection against severe pertussis.

• Keywords
• Hospital surveillance, Pertussis, Vaccine effectiveness, Vaccine in pregnancy, Whooping cough,
• MeSH
• Hospitalization MeSH
• Humans MeSH
• Mothers MeSH
• Whooping Cough * epidemiology   MeSH
• Pertussis Vaccine MeSH
• Case-Control Studies MeSH
• Pregnancy MeSH
• Vaccination MeSH
• Check Tag
• Humans MeSH
• Pregnancy MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Pertussis Vaccine MeSH

IntroductionPERTINENT is a pilot active surveillance system of infants hospitalised with pertussis in six European Union/European Economic Area countries (37 hospitals, seven sites).AimThis observational study aimed to estimate annual pertussis incidence per site from 2016 to 2018 and respective trends between 2017 and 2018. Pertussis cases were described, including their severity.MethodsWe developed a generic protocol and laboratory guidelines to harmonise practices across sites. Cases were hospitalised infants testing positive for Bordetella pertussis by PCR or culture. Sites collected demographic, clinical, laboratory data, vaccination status, and risk/protective factors. We estimated sites' annual incidences by dividing case numbers by the catchment populations.ResultsFrom December 2015 to December 2018, we identified 469 cases (247 males; 53%). The median age, birthweight and gestational age were 2.5 months (range: 0-11.6; interquartile range (IQR): 2.5), 3,280 g (range: 700-4,925; IQR: 720) and 39 weeks (range: 25-42; IQR: 2), respectively. Thirty cases (6%) had atypical presentation either with cough or cyanosis only or with absence of pertussis-like symptoms. Of 330 cases with information, 83 (25%) were admitted to intensive care units including five deceased infants too young to be vaccinated. Incidence rate ratios between 2018 and 2017 were 1.43 in Czech Republic (p = 0.468), 0.25 in Catalonia (p = 0.002), 0.71 in France (p = 0.034), 0.14 in Ireland (p = 0.002), 0.63 in Italy (p = 0.053), 0.21 in Navarra (p = 0.148) and zero in Norway.ConclusionsIncidence appeared to decrease between 2017 and 2018 in all but one site. Enhanced surveillance of hospitalised pertussis in Europe is essential to monitor pertussis epidemiology and disease burden.

• Keywords
• active surveillance, hospital surveillance, pertussis, pertussis incidence,
• MeSH
• Bordetella pertussis MeSH
• European Union MeSH
• Hospitalization MeSH
• Incidence MeSH
• Infant MeSH
• Humans MeSH
• Hospitals MeSH
• Infant, Newborn MeSH
• Whooping Cough * diagnosis   epidemiology   prevention & control   MeSH
• Pertussis Vaccine MeSH
• Aged MeSH
• Vaccination MeSH
• Check Tag
• Infant MeSH
• Humans MeSH
• Male MeSH
• Infant, Newborn MeSH
• Aged MeSH
• Publication type
• Journal Article MeSH
• Case Reports MeSH
• Observational Study MeSH
• Geographicals
• Czech Republic MeSH
• Europe MeSH
• France MeSH
• Ireland MeSH
• Italy MeSH
• Norway MeSH
• Names of Substances
• Pertussis Vaccine MeSH