Calculation of Reproductive Number Using Data from H1N1 Patients in Fars Province, Southern Iran

Effective reproductive number (Re) is an index which considers the proportion of susceptible people in a community. There are different methods for calculation of basic reproductive number. The aim of this study was to evaluate the reproductive number using data from H1N1 patients in Fars Province, southern Iran. According to the data obtained, 233 cases were confirmed between July 15th and December 3rd, 2009. Two waves were observed during this period with a peak in October 21st in Fars Province. In the first wave, the highest amount of R0 was 3.22 and the lowest amount was 2.12 and in the second wave, the highest and lowest amounts of R0 were 3.42 and 2.42, respectively. Effective reproductive number could not be more than 1.54. Thus in order to maintain R0 below 1, using preventive measures like vaccination, only 70% of population should be immune. As 54.9% of Fars population were immune against H1N1 if only 15.1 of them take part in vaccination program, the disease will not reach an epidemic level.