Varicella-zoster virus susceptibility and primary healthcare consultations in Norway.
Currently Norway does not recommend universal varicella vaccination for healthy children. This study assessed susceptibility to varicella-zoster virus (VZV) in the Norwegian population for the first time.



A national convenience sample of residual sera was tested for anti-VZV IgG by ELISA. We estimated age-specific seropositivity to VZV, controlling for sex and geographical distribution. We assessed differences between the proportions using the chi-square test and multivariable logistic regression. Seroprevalence data were compared to the varicella and herpes zoster-associated consultation rates in patients attending primary healthcare.



Although 73.2 % (n = 1,540) of all samples were positive for VZV, only 11.2 % of samples collected from 1-year-olds were seropositive. There was a sharp increase in the proportion of seropositive in 3- and 5-year-olds (40.2 % and 65.4 %, respectively). By the school entry age of 6 years, 69.8 % of children were seropositive. The age-specific annual consultation rate for varicella in primary healthcare peaked in 1-year-olds, with 2,627 cases per 100,000 population. The profile of varicella-related consultations in primary healthcare mirrored the VZV seropositivity profile. The herpes zoster-related consultations in primary healthcare peaked in people over 70 years of age (702 cases per 100,000 population).



VZV seroprevalence in Norway was somewhat lower than in some other European countries. The age-specific varicella-related consultation rates in primary healthcare mirrored the age profile of VZV seroprevalence.
Norwegian Institute of Public Health, Infection Control and Environmental Health, PO Box 4404, NO-0403, Oslo, Norway. Grazina.Rimseliene@fhi.no.
Grazina
G
Rimseliene
Norwegian Institute of Public Health, Infection Control and Environmental Health, PO Box 4404, NO-0403, Oslo, Norway.
Kirsti
K
Vainio
Norwegian Institute of Public Health, Infection Control and Environmental Health, PO Box 4404, NO-0403, Oslo, Norway.
Moustafa
M
Gibory
Norwegian Institute of Public Health, Infection Control and Environmental Health, PO Box 4404, NO-0403, Oslo, Norway.
Beatriz Valcarcel
BV
Salamanca
Norwegian Institute of Public Health, Infection Control and Environmental Health, PO Box 4404, NO-0403, Oslo, Norway.
Elmira
E
Flem
D000293:Adolescent; D000367:Age Factors; D016009:Chi-Square Distribution; D019433:Chickenpox Vaccine / Q000191:economics / Q000600:supply & distribution*; D002648:Child; D002662:Child Health Services / Q000706:statistics & numerical data; D002675:Child, Preschool; D004198:Disease Susceptibility; D005260:Female; D006562:Herpes Zoster / Q000097:blood / Q000453:epidemiology* / Q000517:prevention & control; D014645:Herpesvirus 3, Human / Q000276:immunology*; D006801:Humans; D007223:Infant; D016015:Logistic Models; D008297:Male; D009664:Norway / Q000453:epidemiology; D011320:Primary Health Care / Q000706:statistics & numerical data; D012017:Referral and Consultation / Q000706:statistics & numerical data; D016036:Seroepidemiologic Studies; D014611:Vaccination
D019433:Chickenpox Vaccine