Vaccination, age, ethnicity, and household size are independent protective/ risk factors for COVID-19 and influenza in New Zealand, according to results of the SHIVERS II, III and IV Prospective Community Cohort Study. Over the period 7 February to 2 October 2022, the adjusted cumulative incidence for COVID-19 in Wellington was 4.5 times higher than for influenza. For COVID-19, the highest incidence was seen in adolescents aged 12-17 years and individuals of European/other ethnicity. For influenza, the highest incidence was seen in children aged 1-4 years and Māori. Risk of COVID-19 infection was 75% higher in adolescents who had received two doses of the COVID-19 vaccine vs adults who had received three doses. Individuals with COVID-19 were less likely to access health care or experience febrile and severe illness than those with influenza, but were more likely to report sore throat, headache, myalgia, and loss of taste or smell.
