S100A8 and infection: 22 The frequency we report is lower than that reported in a northeastern region of Brazil (96.7%)30,31 but higher than that reported in Mexico (47.6% to 73.9%).12,32-34 Differences in regional distribution of strains are clear: The frequency of cagA-positive HP is 90% to 95% in Asian countries, whereas only it is 50% to 60% in Western countries5,34a,35; however, we did not find differences in cagA+ infection rates among Peruvian regions nor among Lima sectors.