Two-dose varicella vaccine effectiveness and rash severity in outbreaks of varicella among public school students

BACKGROUND

Universal 2-dose varicella vaccination was recommended in 2006 to further reduce varicella disease burden. This study examined 2-dose varicella vaccine effectiveness (VE) and rash severity in the setting of school-associated varicella outbreaks.

METHODS

A case control study was conducted from January 2010 to May 2011 in all West Virginia public schools. Clinically diagnosed cases from varicella outbreaks were matched with classmate controls. Vaccination information was collected from school, health department and healthcare provider immunization information systems.

RESULTS

Among the 133 cases and 365 controls enrolled, VE against all varicella was 83.2% [95% confidence interval (CI): 69.2%-90.8%] for 1-dose of varicella vaccine and 93.9% (95% CI: 86.9%-97.1%) for 2-dose; the incremental VE (2-dose vs. 1-dose) was 63.6% (95% CI: 32.6%-80.3%). In preventing moderate/severe varicella, 1-dose varicella vaccine was 88.2% (95% CI: 72.7%- 94.9%) effective, and 2-dose vaccination was 97.5% (95% CI: 91.6%-99.2%) effective, with the incremental VE of 78.6% (95% CI: 40.9%-92.3%). One-dose VE declined along with time since vaccination (VE = 93.0%, 88.0% and 81.8% in <5, 5-9 and ≥ 10 years after vaccination, P = 0.001 for trend). Both 1- and 2-dose breakthrough cases had milder rash than unvaccinated cases (<50 lesion: 24.6%, 49.1% and 70.0% in unvaccinated, 1-dose and 2-dose cases, P < 0.001), and no severe disease was found in 2-dose cases.

CONCLUSIONS

Two-dose varicella vaccination is highly effective and confers higher protection than a 1-dose regimen. High 2-dose varicella vaccination coverage should maximize the benefits of the varicella vaccination program and further reduce varicella disease burden in the United States.

Severe methicillin-susceptible Staphylococcus aureus infections associated with epidural injections at an outpatient pain clinic

BACKGROUND

Recent outbreaks in ambulatory care settings have highlighted infection control breaches as risk factors for disease transmission. In May 2009, 3 patients were hospitalized with severe methicillin-susceptible Staphylococcus aureus (MSSA) infections after receiving epidural injections at a West Virginia outpatient pain clinic.

METHODS

We conducted a retrospective cohort study evaluating clinic patients who received injections during a 3-week period. A case was defined as laboratory-confirmed infection or clinical evidence of infection ≤ 14 days after a patient received an injection. Infection control procedures were assessed. MSSA isolates from patient infections and clinic staff nasal swabs were genotyped by using pulsed-field gel electrophoresis.

RESULTS

Eight (7%) of 110 cohort patients met the case definition; 6 (75%) cases were laboratory confirmed. Eight (12%) of 69 patients who received epidural injections were case patients compared with none of the other 41 patients (P = .02). During procedures, staff use of face masks and preparation of patient skin were suboptimal; epidural injection syringes were reused to access shared medication vials. MSSA isolates from 2 patients and 1 staff member were indistinguishable by pulsed-field gel electrophoresis.

CONCLUSION

Infection control breaches likely facilitated MSSA transmission to patients receiving epidural injections. Adhering to correct infection control practices in ambulatory care settings is critical to prevent disease transmission.

Infarct distribution in subhuman primates after acute coronary occlusion

The extent of epicardial, endocardial and septal infarct was determined in 24 monkeys and five baboons 1 week after acute left anterior descending or diagonal branch coronary artery ligation. All 24 Macaca cynmologous monkeys had non-dominant left anterior descending coronary arteries. A snare ligature was placed just distal to the first diagonal branch for varying time periods (1, 2, 4, and 6 h followed by reperfusion or left in place permanently). In five baboons a chronic ligature was placed around a diagonal branch. All animals lived and were killed a week later. Histological mapping and planimetry of serial cross-sections were employed to quantify the extent and distribution of the infarct. All infarcts were transmural. The extent of epicardial infarct was significantly greater than the extent of endocardial infarct for 2 h ligations (3.5 +/- 0.87% of the left ventricle versus 2.4 +/- 0.58% of the left ventricle, P less than 0.05), the chronic left anterior descending coronary artery ligations (5.4 +/- 1.06% of the left ventricle versus 4.5 +/- 0.92% of the left ventricle, P less than 0.05 and for the chronic diagonal branch ligations (4.06 +/- 0.66% of the right ventricle + left ventricle versus 2.64 +/- 0.51+ of the right ventricle + left ventricle, P less than 0.02). It is evident, however, that the magnitude of this epicardial preponderance was not great and that, in general, the infarcts were transmural and rectangular in configuration.

Blood microaggregates and ultrafilters

The report presents three studies of post-traumatic pulmonary insufficiency (PTPI). In the first no significant pulmonary hemodynamic or ventilatory changes in severely shocked baboons resuscitated with shed fresh blood or stored blood were observed over 48 or 84 hours. Second, a post-mortem study of patients receving more than 5 units of blood within 24 hours of death showed sme microemboli in the lungs in about two thirds. Patients with multiple microthrombi had received an average of 20.6 units of blood; patients with some or no microemboli 15.5 and 6.3, respectively. Third in a review of the respiratory complications of 153 multiple-trauma patients, it was shown that the formerly severe problems with PTPI were now well managed clinically, that persistent respiratory failure was now occurring much later after injury, and occurred almost exclusively in patients with sepsis. Relation of the above data to previous reports in the literature led to the conclusion that the clinical significance of microaggregates in stored blood, if any, is low, and that ultrafiltration to remove microemboli only makes sense if it does not impede the rate of blood infusion and does not increase cost.