Table 5 Interaction between influenza vaccination and season for all-cause mortality rates and death associated with a respiratory event in patients with chronic obstructive pulmonary disease aged at least 40 years
December to NovemberDecember to MarchApril to NovemberDecember to March vs April to November
Patients not vaccinated against pneumonia
    Deaths0.79 (0.77 to 0.80)0.59 (0.57 to 0.61)0.97 (0.94 to 1.00)0.60 (0.58 to 0.63)
    Deaths associated with a respiratory event0.82 (0.77 to 0.86)0.60 (0.53 to 0.68)1.03 (0.96 to 1.11)0.61 (0.55 to 0.68)
    Deaths with a respiratory event recorded as cause of death0.80 (0.70 to 0.92)0.61 (0.51 to 0.75)0.98 (0.83 to 1.17)0.63 (0.49 to 0.81)
Patients vaccinated against pneumonia
    Deaths0.46 (0.44 to 0.48)0.30 (0.28 to 0.32)0.64 (0.60 to 0.68)0.47 (0.43 to 0.51)
    Deaths associated with a respiratory event0.47 (0.42 to 0.52)0.32 (0.28 to 0.37)0.65 (0.56 to 0.76)0.49 (0.40 to 0.60)
    Deaths with a respiratory event recorded as cause of death0.50 (0.48 to 0.52)0.37 (0.30 to 0.46)0.63 (0.510.79)0.59 (0.43 to 0.80)