Table 2 Summary of studies reporting reporting incidence of influenza virus infection using serology
From: Incidence of influenza virus infection among pregnant women: a systematic review
Study | Number of cases | Denominator | Crude incidence rate (CI) (aor derived from %) | 95% CI | Pandemic or seasonal? | Study design | Grading system and scoreb | Hospital-basSummary of studies reporting repored or clinic-based? | Duration of surveillance (months or years) | Country |
|---|---|---|---|---|---|---|---|---|---|---|
Griffiths 1980 | 77 | 1,595 | 483 per 10,000 pregnanciesa | (399–614) | Seasonal | Cohort | NOS = 7 | Hospital | 3 years (22 months total influenza season) | UK |
Hardy 1961 | 61 | 671 | 909 per 10,000 pregnanciesa | (716–1,155) | Pandemic | Cohort | NOS = 6 | Clinic | 5 months | US |
Irving 2000 | 182 | 1,659 | 1,097 per 10,000 pregnanciesa | (957–1,258) | Seasonal | Cohort | NOS = 7 | Hospital | 15 months | UK |