Controlled Trial of Inactivated Influenza Vaccine Containing the a/Hong Kong Strain During an Outbreak of Influenza Due to the a/England/42/72 Strain

Repeated annual influenza vaccination and vaccine effectiveness: review of evidence

“…The initial publication described a 3-year randomized clinical trial that began in October 1970 [6]. Participating youth, 11-19 years old, were randomly assigned to receive a subcutaneous dose of whole virus inactivated vaccine containing either influenza A or B.…”

Protection Against Influenza After Annually Repeated Vaccination

“…For the past 20 years, the articles by Hoskins et al 4,19,20 have caused doubts about the common policy of -H3N2), the attack rate was indeed higher in groups with multiple vaccinations than in those with single vaccination, but the difference was not significant (F-2, Tables 1 and 2). A simultaneous influenza B outbreak could not be evaluated because of the lack of a group with multiple vaccinations.…”

“…[19][20][21][22][23][24][25][26][27] Nine trials were conducted in subjects of various age classes and different health states. "Influenzarelated cases" were defined as incidents of influenzalike illness with or without laboratory confirmation in 6 articles [19][20][21][22][23]25 or as occurrences of death clinically related to influenza. 24 Two of the trials cumulated 3 observational years.…”

Immunity to challenge in volunteers vaccinated with an inactivated current or earlier strain of influenza A(H3N2)

“…There is evidence that at the time of major antigenic shift vaccines made with 'obsolete' strains do not protect and this was seen when the Hong Kong (H3N2) virus (HK) appeared (Mostow et al 1969; Tyrrell, Buckland, Rubenstein & Sharpe, 1970). In periods of antigenic drift vaccines made against earlier strains may give protection (Stiver, Graves, Eickhoff & Meiklejohn, 1973), for instance three annual doses of HK vaccine protected schoolboys against the A/Eng/42/72 serotype (Hoskins et al, 1973). However at present it is not * Present address: Servier Laboratories Ltd, Servier House, Horsenden Lane South, Greenford, Middlesex UB6 7PW. possible to define the degree of antigenic difference between two strains which is compatible with effective protection.…”