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1.  Think globally, act locally: the role of local demographics and vaccination coverage in the dynamic response of measles infection to control 
The global reduction of the burden of morbidity and mortality owing to measles has been a major triumph of public health. However, the continued persistence of measles infection probably not only reflects local variation in progress towards vaccination target goals, but may also reflect local variation in dynamic processes of transmission, susceptible replenishment through births and stochastic local extinction. Dynamic models predict that vaccination should increase the mean age of infection and increase inter-annual variability in incidence. Through a comparative approach, we assess national-level patterns in the mean age of infection and measles persistence. We find that while the classic predictions do hold in general, the impact of vaccination on the age distribution of cases and stochastic fadeout are mediated by local birth rate. Thus, broad-scale vaccine coverage goals are unlikely to have the same impact on the interruption of measles transmission in all demographic settings. Indeed, these results suggest that the achievement of further measles reduction or elimination goals is likely to require programmatic and vaccine coverage goals that are tailored to local demographic conditions.
PMCID: PMC3720039  PMID: 23798689
measles; elimination; vaccination; mean age at infection
2.  Effect of age on intraoperative cerebrovascular autoregulation and near-infrared spectroscopy-derived cerebral oxygenation 
BJA: British Journal of Anaesthesia  2011;107(5):742-748.
Age is an important risk factor for perioperative cerebral complications such as stroke, postoperative cognitive dysfunction, and delirium. We explored the hypothesis that intraoperative cerebrovascular autoregulation is less efficient and brain tissue oxygenation lower in elderly patients, thus, increasing the vulnerability of elderly brains to systemic insults such as hypotension.
We monitored intraoperative cerebral perfusion in 50 patients aged 18–40 and 77 patients >65 yr at two Swiss university hospitals. Mean arterial pressure (MAP) was measured continuously using a plethysmographic method. An index of cerebrovascular autoregulation (Mx) was calculated based on changes in transcranial Doppler flow velocity due to changes in MAP. Cerebral oxygenation was assessed by the tissue oxygenation index (TOI) using near-infrared spectroscopy. End-tidal CO2, O2, and sevoflurane concentrations and peripheral oxygen saturation were recorded continuously. Standardized anaesthesia was administered in all patients (thiopental, sevoflurane, fentanyl, atracurium).
Autoregulation was less efficient in patients aged >65 yr [by 0.10 (se 0.04; P=0.020)] in a multivariable linear regression analysis. This difference was not attributable to differences in MAP, end-tidal CO2, or higher doses of sevoflurane. TOI was not significantly associated with age, sevoflurane dose, or Mx but increased with increasing flow velocity [by 0.09 (se 0.04; P=0.028)] and increasing MAP [by 0.11 (se 0.05; P=0.043)].
Our results do not support the hypothesis that older patients' brains are more vulnerable to systemic insults. The difference of autoregulation between the two groups was small and most likely clinically insignificant.
PMCID: PMC3192482  PMID: 21835838
age groups; anaesthesia; cerebrovascular circulation
3.  More on measles. 
Public Health Reports  1999;114(1):4-5.
PMCID: PMC1308335  PMID: 9925159
4.  Haemophilus influenzae invasive disease in the United States, 1994-1995: near disappearance of a vaccine-preventable childhood disease. 
Emerging Infectious Diseases  1998;4(2):229-237.
We analyzed national Haemophilus influenzae (Hi) surveillance data from 1994 and 1995 to describe the epidemiology of Hi invasive disease among persons of all ages. Serotype data were available for 376 (56%) of 669 reported Hi cases among children aged 4 years or younger; 184 (49%) were H. influenzae type b (Hib). Among children aged 4 or younger, incidence (per 100,000) of all Hi invasive disease was 1.8 in 1994 and 1.6 (p < 0.05) in 1995. Children aged 5 months or younger had the highest average annual incidence rate of Hib invasive disease (2.2 per 100,000); children aged 6 to 11 months had the next highest rate (1.2 per 100,000)(p < 0.05). Of 181 children with Hib invasive disease whose age in months was known, 85 (47%) were too young (aged 5 months or younger) to have completed a primary series with an Hib-containing vaccine. Of the 83 children with known vaccination status who were eligible to receive a primary series (aged 6 months or older), 52 (63%) were undervaccinated, and the remaining 31 (37%) had completed a primary series in which vaccine failed. Among persons aged 5 years or older with Hi invasive disease, the lowest average annual incidence was among those 20 to 39 years of age (0.15 per 100,000), and the highest was among those aged 80 years or older (2.26 per 100,000). Among persons aged 5 years or older, serotype data were available for 1,372 (71%) of the 1,940 Hi invasive disease cases; 159 (28%) of the 568 Hi cases with known serotype were due to Hib.
PMCID: PMC2640137  PMID: 9621193
5.  Exudative pharyngitis possibly due to Corynebacterium pseudodiphtheriticum, a new challenge in the differential diagnosis of diphtheria. 
Emerging Infectious Diseases  1997;3(1):65-68.
Corynebacterium pseudodiphtheriticum has rarely been reported to cause disease in humans, despite its common presence in the flora of the upper respiratory tract. We report here a case of exudative pharyngitis with pseudomembrane possibly caused by C. pseudodiphtheriticum in a 4-year-old girl. The case initially triggered clinical and laboratory suspicion of diphtheria. Because C. pseudodiphtheriticum can be easily confused with Corynebacterium diphtheriae in Gram stain, clarification of its role in the pathogenesis of exudative pharyngitis in otherwise healthy persons is of public health importance. Simple and rapid screening tests to differentiate C. pseudodiphtheriticum from C. diphtheriae should be performed to prevent unnecessary concern in the community and unnecessary outbreak control measures.
PMCID: PMC2627595  PMID: 9126447
6.  Determinants of cigarette smoking in the black township population of Cape Town. 
There is concern about the increasing tobacco consumption in developing countries, especially in urban communities. Little information is available on the prevalence and determinants of smoking in black townships in South Africa. We therefore conducted a survey of the smoking practices in three such townships in Cape Town, in which 673 higher primary schoolchildren and 1320 adults were interviewed using a WHO questionnaire translated into Xhosa. Results were analysed using a multiple logistic regression model. In higher primary schoolpupils, boys smoked much more than girls [adjusted odds ratio (ORa) = 17.8; 95% confidence interval (CI): 5.2-60.9]; and smoking prevalence increased with age (ORa = 1.6; 95% CI: 1.3-1.9), peer pressure (ORa = 4.4; 95% CI: 1.9-6.9), and poor health knowledge (ORa = 3.1; 95% CI: 1.6-5.8). In adults, smoking prevalence was 53% in men compared to 6% in women. In men, an urban experience of 6 or more years was significantly associated with smoking (ORa = 1.9; 95% CI: 1.2-3.0) after adjustment for age, health knowledge and occupation. No association was found between level of education and smoking prevalence. Men in higher paid occupations smoked more than those in low paid occupations (ORa = 1.7; 95% CI: 1.0-2.8). Unemployment, however, was not associated with smoking prevalence. The findings emphasise the need for primary prevention of smoking in women and boys. Urbanisation and increased earning power appear to boost tobacco consumption in the absence of active anti-smoking efforts.
PMCID: PMC1052837  PMID: 2607296

Results 1-6 (6)