[Study on pricing and uptake rate of influenza vaccination for the elderly in Japan with a simple random sampling...

In 2001, Japan launched a nationwide subsidy program for influenza immunization of the elderly, whose implementation was devolved to municipalities. Rapid appraisal of the financial impact and utilisation are helpful for evaluating public programs. The government appraised uptake rate with a resource-consuming complete survey. In the present study, the authors carried out a simple and easy sample survey, with a simple random sampling method, to estimate averages of co-payment, subsidy, and total price for one vaccination. The utility of a simple random sampling method for a nationwide survey is also discussed.

A total of 300 individuals were randomly selected from about 22 million senior citizens in the 2001/2 season. A questionnaire is sent to their municipal authorities, inquiring about the price of vaccination, the target population size, and the numbers of vaccinated seniors from 2001/2 to 2004/5. Annual changes and the differences between urban and rural areas were examined with analysis of variance and regression analysis.

The response rate is 94.0%. Nationwide average prices of vaccination in terms of co-payment, subsidy, and total price changes from 2001/2 to 2004/5 were as follows: the co-payments were yen 1134, yen 1136, yen 1139, yen 1129 and yen 1148; the subsidies were yen 2972, yen 2955, yen 2966, yen 2954 and yen 2941; and the total prices are yen 4194, yen 4169, yen 4178, yen 4156 and yen 4142. No statistically significant differences were found in the annual rates. Vaccine uptake rates from 2001/2 to 2003/4 were 29.9%, 37.8%, 46.1%, 49.6%, showing a statistically significant increase.

These are the first estimates of price and uptake rates of influenza vaccination for the elderly in Japan by a sample survey method. The results demonstrate that the co-payment, subsidies, and the total price have not changed significantly since the program started, but that uptake has improved. The results also suggest that simple random sampling methods are useful for rapid appraisal of the nationwide trends with public programs devolved to municipalities.