title: Impact and Effectiveness of Monovalent Rotavirus Vaccine in Armenian Children.
abstract: BACKGROUND
  The Republic of Armenia was 1 of the 2 earliest countries in the Newly Independent States to introduce rotavirus vaccine into its national immunization program to reduce the burden of rotavirus disease (documented to cause 38% of acute gastroenteritis hospitalizations [AGE] among children aged <5 years). In November 2012, RV1 (Rotarix) was introduced for Armenian infants at ages 6 and 12 weeks.
  
  
  METHODS
  The established active surveillance system at 2 hospitals in the capital, Yerevan, whereby children aged <5 years hospitalized for AGE have stool sample tested for rotavirus antigen, was used to assess trends in rotavirus hospitalizations. Immunization records on children enrolled after vaccine introduction were obtained from clinics, and vaccine effectiveness (VE) was estimated using children with AGE who test negative for rotavirus as controls for the rotavirus-positive cases.
  
  
  RESULTS
  Among infants, rotavirus hospitalizations were reduced by 48% within the first year after introduction, and by ≥75% in years 2 and 3 following introduction. Reductions of ≥30% in other young children too old to have been vaccinated suggest additional benefit through indirect protection; overall in year 3, rotavirus hospitalizations were reduced by 69% among children aged <5 years. The overall VE of 2 RV1 doses in protecting against rotavirus hospitalization (any severity) was 62% (95% confidence interval [CI], 36%-77%) among children aged 6-23 months; 68% (95% CI, 24%-86%) among those aged 6-11 months, and 60% (95% CI, 20%-80%) in children aged 12-23 months. Against more severe rotavirus disease, VE was 79% (95% CI, 55%-90%) and similarly high in both age groups.
  
  
  CONCLUSIONS
  RV1 is effective in young Armenian children and substantially reduced rotavirus hospitalizations shortly after introduction.
authors.affiliation: National Immunization Program National Centre of Disease Control and Prevention Ministry of Health of the Republic of Armenia.
authors.forename: Gayane
authors.initials: G
authors.lastname: Sahakyan
authors.affiliation: National Centre of Disease Control and Prevention Ministry of Health of the Republic of Armenia Immunization and Epidemiology of Vaccine-Preventable Diseases, Yerevan, Armenia.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Grigoryan
authors.affiliation: Vaccine-Preventable Diseases and Immunization, World Health Organization Regional Office for Europe, Copenhagen, Denmark.
authors.forename: Annemarie
authors.initials: A
authors.lastname: Wasley
authors.affiliation: Vaccine-Preventable Diseases and Immunization, World Health Organization Regional Office for Europe, Copenhagen, Denmark.
authors.forename: Liudmila
authors.initials: L
authors.lastname: Mosina
authors.affiliation: National Centre of Disease Control and Prevention Ministry of Health of the Republic of Armenia.
authors.forename: Shushan
authors.initials: S
authors.lastname: Sargsyan
authors.affiliation: Nork Infection Hospital, Country Office of Armenia, Yerevan.
authors.forename: Ara
authors.initials: A
authors.lastname: Asoyan
authors.affiliation: Nork Infection Hospital, Country Office of Armenia, Yerevan.
authors.forename: Zaruhi
authors.initials: Z
authors.lastname: Gevorgyan
authors.affiliation: Arabkir Medical Centre, Country Office of Armenia, Yerevan.
authors.forename: Karine
authors.initials: K
authors.lastname: Kocharyan
authors.affiliation: World Health Organization, Country Office of Armenia, Yerevan.
authors.forename: Tigran
authors.initials: T
authors.lastname: Avagyan
authors.affiliation: Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Lopman
authors.affiliation: National Centre of Disease Control and Prevention Ministry of Health of the Republic of Armenia.
authors.forename: Artavazd
authors.initials: A
authors.lastname: Vanyan
authors.affiliation: Ministry of Health of the Republic of Armenia.
authors.forename: Sergey
authors.initials: S
authors.lastname: Khactatryan
authors.affiliation: Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Umesh D
authors.initials: UD
authors.lastname: Parashar
authors.affiliation: Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Cortese
mesh_terms: D000956:Antigens, Viral / Q000276:immunology; D001136:Armenia / Q000453:epidemiology; D002675:Child, Preschool; D003967:Diarrhea / Q000453:epidemiology / Q000517:prevention & control / Q000821:virology; D062665:Epidemiological Monitoring; D005243:Feces / Q000821:virology; D005759:Gastroenteritis / Q000453:epidemiology / Q000517:prevention & control* / Q000821:virology; D006760:Hospitalization / Q000639:trends; D006801:Humans; D017589:Immunization Programs; D007223:Infant; D008297:Male; D012401:Rotavirus / Q000276:immunology; D012400:Rotavirus Infections / Q000453:epidemiology / Q000208:ethnology / Q000517:prevention & control* / Q000821:virology; D022243:Rotavirus Vaccines / Q000008:administration & dosage / Q000276:immunology*; D014611:Vaccination / Q000639:trends; D064166:Vaccine Potency; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000956:Antigens, Viral; C492457:RIX4414 vaccine; D022243:Rotavirus Vaccines; D014613:Vaccines, Attenuated
keywords: Armenia; effectiveness; impact; rotavirus vaccine