Given a passage, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

[Q]: The live oral rotavirus (RV) vaccines have shown a reduced efficacy in Africa. Recent in vitro studies have shown binding of the RV surface protein (VP4) to histo-blood group antigens (HBGAs) in an RV genotype-dependent manner, suggesting them to be putative receptors for RV. The diversity of HBGA phenotypes in different ethnic populations, combined with prevalence/absence of specific RV genotypes, led us to hypothesize whether the genetic variations in HBGAs in a population limit susceptibility to certain RV genotypes, plausibly leading to reduced vaccine efficacy.', 'Association between HBGAs status and susceptibility to RV P genotypes was investigated in children in Burkina Faso and Nicaragua. In total, 242 children with diarrhea in Burkina Faso and Nicaragua were investigated, 93 of whom were RV positive.', 'In Burkina Faso, the P[8] RV strains (n = 27) infected only Lewis- and secretor-positive children (27/27; P < .0001), but no Lewis-negative children. In contrast, the P[6] strains (n = 27) infected predominantly Lewis-negative children (n = 18; P < .0001) but also Lewis-positive children, irrespective of their secretor status. The results from Nicaragua confirmed that all P[8]-infected children (n = 22) were secretor Lewis positive.
[A]: Do both Lewis and secretor status mediate susceptibility to rotavirus infections in a rotavirus genotype-dependent manner?


[Q]: Beta blockers and calcium antagonists are widely used in the management of angina pectoris in the belief that the combination is more efficacious than either drug alone.', 'This double blind randomised crossover placebo controlled study compares the effects of nicardipine, atenolol and their combination in 30 patients with chronic stable angina. Each treatment period lasted 6 weeks with dose titration after 3 weeks. Symptom limited treadmill exercise testing and radionuclide ventriculography at rest was carried out at the end of each treatment period.', 'Total exercise duration and time to 1-mm ST-segment depression was significantly prolonged by nicardipine and atenolol when compared to placebo, the combination offered no additional benefit. Time to onset of angina was significantly prolonged by nicardipine and the combination but not by atenolol. Indices of left ventricular function were not significantly affected by any treatment other than an increase in left ventricular end diastolic volume on atenolol and the combination.
[A]: Is atenolol or nicardipine alone as efficacious in stable angina as their combination : a double blind randomised trial?


[Q]: To investigate the associations between C-reactive protein (CRP), homocysteine levels, use of hormone therapy (HT) and other factors.', "A 12-year prospective study of 438 Australian-born women (Melbourne Women's Midlife Health Project), who at baseline were aged 45-55 years, had menstruated in the previous 3 months and were not taking HT. Fasting blood was collected in the 11th follow-up year for CRP, homocysteine, estradiol and follicle stimulating hormone (FSH) levels. Physical measurements and face-to-face interviews obtained information on health and lifestyle variables.", 'A total of 258 women (mean age 60 years) participated in the 11th follow-up year. Multiple regression analysis found that CRP levels were positively associated with body mass index (p < 0.001), HT use (p < 0.01), and negatively associated with statin use (p < 0.005) and exercising (p < 0.05). In postmenopausal women currently not using HT (n = 173) and after adjusting for body mass index, exercise and smoking, CRP was negatively associated with FSH levels (beta = -0.32, p < 0.05). Homocysteine levels were positively associated with smoking (p < 0.001) and negatively associated with HT use (p < 0.05).
[A]:
Are serum C-reactive protein and plasma homocysteine levels associated with hormone therapy use and other factors : a population-based study of middle-aged Australian-born women?