Fátima Irisarri

Effectiveness of the 7-Valent Pneumococcal Conjugate Vaccine: A Population-Based Case-Control Study

BACKGROUND The 7-valent pneumococcal conjugate vaccine (PCV7) has shown high efficacy in preventing invasive pneumococcal disease (IPD) caused by vaccine serotypes. We aimed to assess the overall effectiveness of PCV7 against IPD in Navarra, Spain. METHODS All children aged <5 years who were diagnosed with IPD during the period 2001-2005 (n=85) and 5 control subjects per case patient (n=425), individually matched by birth date and birth hospital, were analyzed. Vaccination records were obtained from the regional immunization registry. Conditional logistic regression was used to estimate odds ratios. RESULTS Eighteen case patients (21%) and 114 control subjects (27%) had received >or=1 dose of PCV7. PCV7 serotypes were responsible for 34 (51%) of the cases in unvaccinated children. The overall effectiveness for case prevention was 31% (odds ratio, 0.69; 95% confidence interval, 0.37-1.27). In a separate analysis, vaccination with PCV7 was 88% effective in preventing IPD due to vaccine serotypes (odds ratio, 0.12; 95% confidence interval, 0.02-0.91) and was associated with a higher risk of IPD due to nonvaccine serogroups (odds ratio, 6.16; 95% confidence interval, 1.63-23.3). CONCLUSIONS These data reveal a higher risk of IPD caused by non-PCV7 serogroups among vaccinated children. Consequently, the overall effectiveness of PCV7 for IPD prevention may be greatly reduced.

Mortality by causes in HIV-infected adults: comparison with the general population

BackgroundWe compared mortality by cause of death in HIV-infected adults in the era of combined antiretroviral therapy with mortality in the general population in the same age and sex groups.MethodsMortality by cause of death was analyzed for the period 1999-2006 in the cohort of persons aged 20-59 years diagnosed with HIV infection and residing in Navarre (Spain). This was compared with mortality from the same causes in the general population of the same age and sex using standardized mortality ratios (SMR).ResultsThere were 210 deaths among 1145 persons diagnosed with HIV (29.5 per 1000 person-years). About 50% of these deaths were from AIDS. Persons diagnosed with HIV infection had exceeded all-cause mortality (SMR 14.0, 95% CI 12.2 to 16.1) and non-AIDS mortality (SMR 6.9, 5.7 to 8.5). The analysis showed excess mortality from hepatic disease (SMR 69.0, 48.1 to 78.6), drug overdose or addiction (SMR 46.0, 29.2 to 69.0), suicide (SMR 9.6, 3.8 to 19.7), cancer (SMR 3.2, 1.8 to 5.1) and cardiovascular disease (SMR 3.1, 1.3 to 6.1). Mortality in HIV-infected intravenous drug users did not change significantly between the periods 1999-2002 and 2003-2006, but it declined by 56% in non-injecting drug users (P = 0.007).ConclusionsPersons with HIV infection continue to have considerable excess mortality despite the availability of effective antiretroviral treatments. However, excess mortality in the HIV patients has declined since these treatments were introduced, especially in persons without a history of intravenous drug use.

Vaccine effectiveness in preventing influenza hospitalizations in Navarre, Spain, 2010-2011: cohort and case-control study.

We evaluated the 2010-2011 seasonal influenza vaccine effectiveness in preventing hospitalizations. Using healthcare databases we defined the target population for vaccination in Navarre, Spain, consisting of 217,320 people with major chronic conditions or aged 60 years and older. All hospitalized patients with influenza-like illness (ILI) were swabbed for influenza testing. A total of 269 patients with ILI were hospitalized and 61 of them were found positive for influenza virus: 58 for A(H1N1)2009 and 3 for B virus. The incidence rates of hospitalization with laboratory-confirmed influenza were compared by vaccination status. In the Cox regression model adjusted for sex, age, children in the household, urban/rural residence, comorbidity, pandemic vaccination, pneumococcal vaccination, outpatient visits and hospitalization in the previous year, the seasonal vaccine effectiveness was 58% (95% CI: 16-79%). The nested test-negative case-control analysis gave an adjusted estimate of 59% (95% CI: 4-83%). These results suggest a moderate effect of the 2010-2011 seasonal influenza vaccine in preventing hospitalization in a risk population. The close estimates obtained in the cohort and the test-negative case-control analyses suggest good control of biases.

Enfermedad neumocócica invasiva en la población menor de 5 años de edad de Navarra (2000-2005): impacto de la vacuna conjugada

BACKGROUND AND OBJECTIVE: The 7-valent pneumococcal conjugate vaccine (PCV7) has been commercialized in Spain since June 2001. We aim to evaluate the impact of this vaccine in the incidence of invasive pneumococcal disease (IPD) in Navarre. POPULATION AND METHOD: The laboratories of microbiology of Navarre declare all the isolations of Streptococcus pneumoniae in samples of normally sterile corporal fluids. We analyzed the incidence of IPD in children younger than 5 years between weeks 41 of 2000 and 40 of 2005. RESULTS: The doses of PCV7 sold up to 2005 would provide a cover of 27% in children younger than 5 years, having assumed 4 dose schedules. In the 5 seasons, 103 cases of IPD were diagnosed. From the 2 first seasons (2000-2002) to the last one (2004-2005) a reduction of 69% in the incidence rate of IPD caused by vaccine serotypes was observed (from 33 to 10 cases by 100,000 children under 5 years; p = 0.003). Between those same periods the incidence of IPD caused by non-vaccine serotypes increased a 36% (from 42 to 57 by 100,000; p = 0.405). The global incidence of IPD diminished a 12% (from 77 to 67 by 100,000; p = 0.689). The percentage of cases that had received PCV7 increased until 45% in season 2004-2005 (p < 0.001). The meningitis and bacteraemic pneumonias supposed 42% of the IPD, without significant changes during the period (p = 0.442). CONCLUSIONS: Since the PCV7 was marketed the pattern of serotypes has changed, but the expected reduction in the total IPD incidence has not been achieved.

Incidencia de la varicela y el herpes zóster antes de la introducción de la vacunación sistemática infantil en Navarra, 2005-2006

Varicella is an acute and highly contagious disease produced by the varicella-zoster virus, which leaves lasting immunity. Herpes zoster is produced by reactivation of a latent infection of the same virus. The introduction of systematic and free vaccination against varicella in children of 15 months in Navarre from 2007 onwards can be expected to produce important epidemiological changes. For this reason we describe the previous epidemiological situation in the period from 2005 to 2006. We analysed all cases of varicella and herpes zoster registered in the electronic clinical files of primary care, in the database of hospital discharges and in the mortality register. Between 2005 and 2006, 9,908 cases of varicella were diagnosed (8.29 annually per 1,000 inhabitants), with 90% in children under 15 years old. There were 80 hospital admissions (8 for every 1,000 cases), complications in 2.5 out of every 1,000 cases, and there was one death due to this cause (0.1 per 1,000 cases). In the same period, 4,959 cases of herpes zoster were diagnosed (4.15 cases per 1,000 inhabitants), half in people over 55 years old. There were 179 hospital admissions (36 per 1,000 cases), whose average age was 77, and 83 presented complications (16.7 per 1,000 cases). This epidemiological pattern is similar to that found in other places before the introduction of the vaccine.

Impact of universal two-dose vaccination on varicella epidemiology in Navarre, Spain, 2006 to 2012

In 2007 in Navarre, Spain, universal varicella vaccination with two doses of Varivax was introduced in the childhood immunisation schedule for children aged 15 months and three years. This study describes changes in the epidemiology of varicella in the period 2006 to 2012 and evaluates vaccination effectiveness using epidemiological surveillance data. The incidence of varicella in children aged 0 to 14 years decreased by 98.1%, from 50.1 cases per 1,000 inhabitants in 2006, to 1.0 per 1,000 in 2012. Children aged one to eight years were the vaccinated cohorts, and their incidence of varicella decreased by 98.5% (p<0.0001). In unvaccinated age groups, important reductions were also achieved between 2006 and 2012: 90.5% (p<0.0001) in infants under one year of age, and 89.4% (p<0.0001) in children aged nine years. In the period 2006 to 2012, the hospital admissions rate for varicella or its complications decreased by 89.0%, and in 2012, there was only one admission of a newborn with neonatal varicella. Vaccine effectiveness for at least one dose was 96.8% (95% confidence interval: 96.3-97.2%). Universal vaccination with two doses has reduced varicella circulation to minimum levels within five years and has proved highly effective.

Effectiveness of the trivalent influenza vaccine in Navarre, Spain, 2010-2011: a population-based test-negative case-control study.

BackgroundSome studies have evaluated vaccine effectiveness in preventing outpatient influenza while others have analysed its effectiveness in preventing hospitalizations. This study evaluates the effectiveness of the trivalent influenza vaccine in preventing outpatient illness and hospitalizations from laboratory-confirmed influenza in the 2010–2011 season.MethodsWe conducted a nested case–control study in the population covered by the general practitioner sentinel network for influenza surveillance in Navarre, Spain. Patients with influenza-like illness in hospitals and primary health care were swabbed for influenza testing. Influenza vaccination status and other covariates were obtained from health care databases. Using logistic regression, the vaccination status of laboratory-confirmed influenza cases was compared with that of test-negative controls, adjusting for age, sex, comorbidity, outpatient visits in the previous 12 months, health care setting, time between symptom onset and swabbing, period and A(H1N1)pdm09 vaccination. Effectiveness was calculated as (1-odds ratio)x100.ResultsThe 303 confirmed influenza cases (88% for A(H1N1)pdm09 influenza) were compared with the 286 influenza test-negative controls. The percentage of persons vaccinated against influenza was 4.3% and 15.7%, respectively (p<0.001). The adjusted estimate of effectiveness was 67% (95% CI: 24%, 86%) for all patients and 64% (95% CI: 8%, 86%) in those with an indication for vaccination (persons age 60 or older or with major chronic conditions). Having received both the 2010–2011 seasonal influenza vaccine and the 2009–2010 pandemic influenza vaccine provided 87% protection (95% CI: 30%, 98%) as compared to those not vaccinated.ConclusionThe 2010–2011 seasonal influenza vaccine had a moderate protective effect in preventing laboratory-confirmed influenza.

Effectiveness of Jeryl Lynn-containing vaccine in Spanish children

We evaluated the effectiveness of the Jeryl Lynn strain vaccine in a large outbreak of mumps in Navarre, Spain, 2006-2008. Each of the 241 cases of mumps occurring in children over 15 months of age born between 1998 and 2005 was compared with 5 controls individually matched by sex, birth date, district of residence and paediatrician. Vaccination history was obtained blindly from clinical records. Conditional logistic regression was used to obtain the matched odds ratios (ORs), and effectiveness was calculated as 1-OR. Some 70% of cases had received one dose of measles-mumps-rubella vaccine, and 24% had received two doses. Overall vaccine effectiveness was 72% (95% CI, 39-87%). Two doses were more effective (83%; 54-94%) than a single dose (66%; 25-85%). Among vaccinated children, risk was higher in those who had received the first dose after 36 months of age (OR=3.1; 1.2-8.4) and those who had received the second dose 3 or more years before study enrolment (OR=10.2; 1.5-70.7). Early waning of immunity in children after the second dose may contribute to reduced vaccine effectiveness for mumps prevention.

Impacto de la vacunación universal frente a la varicela en Navarra, 2006-2010

Background. In 2007 universal vaccination against chicken pox was introduced in the vaccine calendar of Navarre. The aim of this study is to evaluate the impact of this measure on the incidence of chicken pox in both the vaccinated cohorts (direct effect) and in the unvaccinated cohorts (indirect effect). Methods. Chicken pox is a disease of individualized compulsory notification. We analyzed the annual incidence by age groups between 2006 and 2010. Hospital admittances with chicken pox or complicated chicken pox as the principal diagnosis were taken from the minimum basic data set on hospital discharges for the years 2006 to 2009. Results. The incidence of chicken pox has fallen by 93.0%, from 8.04 cases per 1,000 inhabitants in 2006 to 0.56 per 1,000 inhabitants in 2010 (p<0,0001). In children from 1 to 6 years (vaccinated cohorts), the incidence of chicken pox has fallen by 96.3%. In the cohorts vaccinated at 10 and 14 years, a fall of 93.6% can also be observed in children from 10 to 14 years, and of 85.0% in those of 15 to 19 years. In the unvaccinated age groups we can observe falls of 88.2% in children under one year, of 73.3% in those of 7 to 9 years, and of 84.6% in people over 20 years. In 2006 there were 25 hospital admissions due to chicken pox in Navarre and in 2009 this figure fell to 7. The rate of admissions fell by 71%. Conclusion. The introduction of universal chicken pox vaccination in Navarre has resulted in a rapid and very steep reduction of the incidence of chicken pox in both vaccinated and unvaccinated people.193BACKGROUND In 2007 universal vaccination against chicken pox was introduced in the vaccine calendar of Navarre. The aim of this study is to evaluate the impact of this measure on the incidence of chicken pox in both the vaccinated cohorts (direct effect) and in the unvaccinated cohorts (indirect effect). MATERIAL AND METHODS Chicken pox is a disease of individualized compulsory notification. We analyzed the annual incidence by age groups between 2006 and 2010. Hospital admittances with chicken pox or complicated chicken pox as the principal diagnosis were taken from the minimum basic data set on hospital discharges for the years 2006 to 2009. RESULTS The incidence of chicken pox has fallen by 93.0%, from 8.04 cases per 1,000 inhabitants in 2006 to 0.56 per 1,000 inhabitants in 2010 (p<0,0001). In children from 1 to 6 years (vaccinated cohorts), the incidence of chicken pox has fallen by 96.3%. In the cohorts vaccinated at 10 and 14 years, a fall of 93.6% can also be observed in children from 10 to 14 years, and of 85.0% in those of 15 to 19 years. In the unvaccinated age groups we can observe falls of 88.2% in children under one year, of 73.3% in those of 7 to 9 years, and of 84.6% in people over 20 years. In 2006 there were 25 hospital admissions due to chicken pox in Navarre and in 2009 this figure fell to 7. The rate of admissions fell by 71%. CONCLUSION The introduction of universal chicken pox vaccination in Navarre has resulted in a rapid and very steep reduction of the incidence of chicken pox in both vaccinated and unvaccinated people.

Effects of previous episodes of influenza and vaccination in preventing laboratory-confirmed influenza in Navarre, Spain, 2013/14 season

We estimated whether previous episodes of influenza and trivalent influenza vaccination prevented laboratory-confirmed influenza in Navarre, Spain, in season 2013/14. Patients with medically-attended influenza-like illness (MA-ILI) in hospitals (n = 645) and primary healthcare (n = 525) were included. We compared 589 influenza cases and 581 negative controls. MA-ILI related to a specific virus subtype in the previous five seasons was defined as a laboratory-confirmed influenza infection with the same virus subtype or MA-ILI during weeks when more than 25% of swabs were positive for this subtype. Persons with previous MA-ILI had 30% (95% confidence interval (CI): -7 to 54) lower risk of MA-ILI, and those with previous MA-ILI related to A(H1N1)pdm09 or A(H3N2) virus, had a, respectively, 63% (95% CI: 16-84) and 65% (95% CI: 13-86) lower risk of new laboratory-confirmed influenza by the same subtype. Overall adjusted vaccine effectiveness in preventing laboratory-confirmed influenza was 31% (95% CI: 5-50): 45% (95% CI: 12-65) for A(H1N1)pdm09 and 20% (95% CI: -16 to 44) for A(H3N2). While a previous influenza episode induced high protection only against the same virus subtype, influenza vaccination provided low to moderate protection against all circulating subtypes. Influenza vaccine remains the main preventive option for high-risk populations.