A cross sectional study among healthy participants randomly selected from the population living in the Nanoro HDSS cohort to (a) study the relation between vaccination and morbidity (including hemoglobin levels, subclinical malaria and stunting) (b) perform hemocytometry in order to determine reference values for that population and estimate the prevalence and causes of anemia, using reference values from other Sub-Sahara Africa countries and industrialized countries.