| Study characteristics |
| Methods |
Prospective cohort study conducted in Saga, Japan. 10,000 community‐dwelling elderly were randomly selected from a population registry and were sent a letter explaining the study with a request for participation. Eligibility criteria were as follows: not being hospitalised, not being institutionalised, not having any long‐term absence, not living alone, and able to contact by telephone at least once a month. |
| Participants |
Among 10,000 elderly citizens, 7357 responded, and 4787 agreed to participate and matched our eligibility criteria. The vaccination status of the study participants was identified by self reporting verification and a list of recipients of partially funded vaccination; 3240 participants (3230 participants were self reported and 10 were known with verification) were vaccinated and 1547 non‐vaccinated. The vaccination coverage was 67.7%. |
| Interventions |
Influenza vaccination versus no vaccination |
| Outcomes |
ILI, clinical influenza, hospitalisation for all causes, hospitalisation for influenza or pneumonia, and total deaths |
| Notes |
The author concludes that influenza vaccination was associated with decreased ILI during the epidemic period in community‐dwelling elderly. The above risk reduction was greater under low‐risk conditions. The results were inconclusive for preventing hospitalisation and death, due to an inadequate sample size. However, our findings support the finding that all elderly individuals substantially benefit from vaccination even in a season of mild influenza activity, and also when the antigenic match between the vaccine strains and the circulating strains is not closely matched. |
