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When using a case-control study design to examine vaccine effectiveness, both the selection of control subjects and the consideration of potential confounders must be the important issues to ensure accurate results. In this report, we described our experience from a case-control study conducted to evaluate the effectiveness of acellular pertussis vaccine combined with diphtheria-tetanus toxoids (DTaP vaccine). Newly diagnosed pertussis cases and age- and sex-matched friend-controls were enrolled, and the history of DTaP vaccination was compared between groups. Logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) of vaccination for development of pertussis. After adjustment for potential confounders, four doses of DTaP vaccination showed a lower OR for pediatrician-diagnosed pertussis (OR = 0.11, 95% CI, 0.01–0.99). In addition, the decreasing OR of four doses vaccination was more pronounced for laboratory-confirmed pertussis (OR = 0.07, 95%CI, 0.01–0.82). Besides, positive association with pertussis was observed in subjects with a history of steroid treatment (OR = 5.67) and those with a recent contact with a lasting cough (OR = 4.12). When using a case-control study to evaluate the effectiveness of vaccines, particularly those for uncommon infectious diseases such as pertussis, the use of friend-controls may be optimal due to the fact that they shared a similar experience for exposure to the pathogen as the cases. In addition, to assess vaccine effectiveness as accurately as possible, the effects of confounding should be adequately controlled with a matching or analysis technique. [ABSTRACT FROM AUTHOR]

Objective The present study aimed to determine the impact of the extent of graft replacement on early and late outcomes in acute DeBakey type I aortic dissection. Methods Between October 1999 and July 2014, 197 consecutive patients were surgically treated for acute DeBakey type I aortic dissection. The extent of graft replacement (hemiarch, partial, or total arch replacement) was mainly determined by the location of the primary entry. Early and late results were compared in patients after total arch replacement (n = 88) and combined hemiarch and partial arch replacement: non–total arch replacement (n = 109). Results The in-hospital mortality rates of the total arch replacement and non–total arch replacement groups were 10.2% and 14.7%, respectively ( P = .47). Multivariate analysis revealed preoperative cardiopulmonary resuscitation and visceral organ malperfusion as significant risk factors for in-hospital mortality, but not total arch replacement. During a mean follow-up period of 60 ± 48 months, the 5-year survivals in the total arch replacement and non–total arch replacement groups were 88.6% ± 4.2% and 83.8% ± 4.4%, respectively ( P = .54). Rates of distal aortic events (defined as freedom from surgery for distal aorta dilation or distal arch diameter expanding to 50 mm) at 5 years were significantly better in the total arch replacement group than in the non–total arch replacement group (94.9% ± 3.5% vs 83.6% ± 4.9%, P = .01). Conclusions The operative mortality of patients with acute DeBakey type I aortic dissection treated by total arch replacement was acceptable with good long-term survival after both total arch replacement and non–total arch replacement. The frequency of distal aortic events might be reduced in patients after total arch replacement compared with non–total arch replacement. [ABSTRACT FROM AUTHOR]

Background The mid-term results of valve-sparing aortic root reimplantation (VSRR) for various indications were investigated. Methods From 2000 to 2013, 183 consecutive patients undergoing VSRR were enrolled. Expanded indications, defined as a patient on the marginal operative indication, included age 65 years or older (n = 33), age 15 years or younger (n = 4), acute type A aortic dissection (AAAD) (n = 21), aortitis (n = 8), reoperative root replacement (n = 11), cusp prolapse (n = 67), large aortoventricular junction of greater than 28 mm (AVJ) (n = 42), preoperative severe aortic regurgitation (AR) (n = 89), left ventricular ejection fraction 0.40 or less (n = 12), LV dilation (n = 66), New York Heart Association class III or greater (n = 5), need for total arch replacement (n = 29), and concomitant mitral valve repair (n = 12). Results The overall survival at 5 years was 96.6%. Freedom from greater than mild AR and reoperation at 5 years was 85.8% and 92.9%, respectively. Cox proportional hazard model revealed that AAAD, cusp prolapse, AVJ 28 mm or greater, and operation before 2009 were at risk for late AR recurrence ( p = 0.015, p = 0.0041, p = 0.032, and p = 0.014, respectively). After 2009, freedom from late AR in the cusp prolapse group improved ( p = 0.055, versus control). Both freedom from recurrent AR and reoperation were worse as the number of expanded indications increased (log-rank trend p = 0.00017 and p = 0.00067, respectively). Conclusions Surgical outcomes of VSRR in these patient cohorts were satisfactory with some room for improvement in patients with cusp prolapse. Although the indications for VSRR are being expanded, a larger number of expanded indications were associated with poor outcomes in terms of longevity of valve function. [ABSTRACT FROM AUTHOR]

In 2008, the number of pertussis cases increased substantially among Japanese adolescents, despite high coverage with acellular pertussis vaccine (DTaP). This study examined the effectiveness of DTaP vaccine in the routine immunization program in Japan. Between April 2009 and October 2012, we conducted a multicenter, case-control study, and compared the history of DTaP vaccination between 55 newly diagnosed pertussis cases and 90 age- and sex-matched controls. DTaP vaccine history was obtained by a self-administered questionnaire completed by their parents or guardians. Logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) of vaccination for development of pertussis. DTaP vaccination of ≥1 dose revealed a significantly lower OR for pertussis (OR = 0.20, 95%CI, 0.04–0.97), and the OR of complete vaccination (4 doses) was 0.22 (0.04–1.05). Even after limiting subjects to those whose vaccination status could be confirmed by the immunization records, the negative associations were observed. The decreasing ORs of 4-dose vaccinees remained, even among subjects who had received the fourth dose ≥9.2 years earlier (OR = 0.11, 95%CI, 0.01–1.02). In conclusion, DTaP vaccination had a preventive effect for pertussis. Effectiveness was observed even 9 or more years after the final dose. [ABSTRACT FROM AUTHOR]

Background In Japan, the seven-valent pneumococcal conjugate vaccine (PCV7) was introduced in 2010. PCV13 has replaced PCV7 since November 2013. Methods The effectiveness of PCV7 in protecting against invasive pneumococcal disease (IPD) in children aged <5 years was evaluated in a nationwide active population-based surveillance of IPD in 2008–2013 in 10 prefectures in Japan. Results 1181 cases were identified; 711 pneumococcal strains were analyzed for serotyping and antimicrobial resistance. Compared with the baseline IPD incidence (25.0 per 100,000), a 98% decline in IPD caused by PCV7 serotypes was found after the introduction of PCV7. This was partially offset by an increased incidence of IPD caused by PCV13 minus PCV7 and non-PCV13 serotypes, resulting in a 57% decline in overall IPD incidence. Absolute increases in the incidence rates of IPD caused by PCV13 minus PCV7 and non-PCV13 serotypes were 2.1 and 2.8 per 100,000 during the study period, respectively. The proportion of meropenem-nonsusceptible strains, especially with serotypes 19A and 15A, increased significantly after PCV7 introduction. Conclusions Our data confirmed a 98% decline in IPD incidence caused by PCV7 serotypes in children aged <5 years and serotype replacement after PCV7 introduction. This shows the importance of continuing surveillance of serotypes responsible for IPD and their antimicrobial resistance in Japan. [ABSTRACT FROM AUTHOR]