Sex: U
Vaccine: FLUX
Symptoms: Nervous system disorder, Polymerase chain reaction, Pyrexia, Vaccination failure, Viral infection
Clinical narrative: On 26 NOV 2008 we received the following information from the above mentioned literature article: This report describes an outbreak of influenza A (H3N2) in December 2005 to January 2006 at a facility housing children and young adults with severe neurologic impairment, where enhanced infection control measures and adamantine prophylaxis were implemented. The circulating virus was subsequently determined as genotypically resistant to adamantanes. In December 2005 the facility housed 98 residents in five units: unit A  on the first floor and units B, C, D and E on the second floor. There were 19 to 21 residents per unit, 1 to 4 residents per room. All residents had severe neurologic impairments and were nonambulatory. Influenza-like illness (ILI) was defined as fever (temperature greater than 38C) plus acute respiratory symptoms. The case definition for a confirmed influenza case was ILI with onset between 12 December 2005 and 12 January 2006 plus a positive test for influenza (rapid antigen test, viral culture of real-time reverse-transcriptase polymerase chain reaction [RT-PCR]). The case definition for a suspect influenza case was ILI with onset, during the investigation period and no other idenfiied etiology among residents who were either not tested for influenza or tested negative by viral culture or RT-PCR. Failure of antiviral prophylaxis was defined as onset of ILI more than 24 h after initiation of prophylaxis. An outbreak of ILI was recognized on the first floor of the facility and reported to the CDPH in December 2005. Rapid antigen tests performed on two residents were positive with influenza A. The circulating strain was confirmed by RT-PCR at the IDPH Laboratory to be influenza A (H3) and CDPH recommended antiviral prophylaxis for asymptomatic residents and unvaccinated staff in Unit A with amantadine or rimantadine. By 3 days after outbreak recognition, 16 (84 per cent) of the 19 residents in Unit A had developed ILI, 11 of whom were confirmed as having influenza A. Four days after outbreak recognition, a resident of Unit E developed ILI and tested positive for influenza A. Antiviral prophylaxis was then recommended for all residents and unvaccinated staff on Unit E. The day after prophylaxis was begun, a roommate of the Unit E case was confirmed to have influenza A, and another case was confirmed on Unit B. At that time, prophylaxis was recommended for all residents and unvaccinated staff on the second floor. Seven additional suspect cases on the second floor were identified retrospectively. Of these, five had tested negative for influenza by both rapid antigen test and RT-PCR. In total, of 79 residents on the second floor, 10 (13 per cent) confirmed and suspect cases were identified. In total, 95 (97 per cent) of the 98 facility residents received the 2005-2006 influenza vaccine in October 2005 including all confirmed and suspect cases. The vaccines were all of a single lot and were administered by facility nursing staff. The outbreak described in this report occurred despite the fact that 97 per cent of residents in the facility had been vaccinated. While influenza immunization remains the primary mechanism of influenza outbreak prevention in closed living communities such as chronic care facilities, residents remain at risk of infection if influenza is introduced into the facility, especially if the strain of influenza introduced does not match the vaccine strains. Even when the infecting strain matches the vaccine strain, the vaccine may have lower efficacy among residents of chronic care facilities. Children at high risk for complications from influenza infection may also have a lower antibody response to the vaccine. Company assessment: Seriousness assessment: Seriousness criterion: medically significant. Causality: not related, influenza is caused by a viral infection. Expectedness assessment according to product information: Influenza is unexpected after vaccination with BEGRIVAC, FLUAD, AGRIPPAL or FLUVIRIN. Vaccination failure and drug ineffective are expected. On a case level, the case is considered unexpected. No change in benefit-risk-ratio. No measures necessary.