Åke Örtqvist1, Rutger Bennet2, Johan Hamrin2, Malin Ryd Rinder3, Hans Lindblad4, Joanna Nederby Öhd5, Margareta Eriksson2. 1. Karolinska Institutet, Department of Medicine, Unit of Infectious Diseases, Karolinska Solna, Stockholm, Sweden; Department of Communicable Disease Control and Prevention, Stockholm County Council, Box 175 33, SE-118 91 Stockholm, Sweden. Electronic address: ake.ortqvist@sll.se. 2. Astrid Lindgren Children's Hospital, Karolinska University Hospital, Solna, SE-171 76 Stockholm, Sweden. 3. Sachs' Children and Youth Hospital, Stockholm South General Hospital, Sjukhusbacken 10, SE-118 83 Stockholm, Sweden. 4. Astrid Lindgren Children's Hospital, Karolinska University Hospital, Huddinge, SE-141 86 Stockholm, Sweden. 5. Department of Communicable Disease Control and Prevention, Stockholm County Council, Box 175 33, SE-118 91 Stockholm, Sweden.
Abstract
BACKGROUND: Immunological studies have indicated that the effectiveness of AS03 adjuvanted monovalent influenza A(H1N1)pdm09 vaccine (Pandemrix) may be of longer duration than what is seen for non-adjuvanted seasonal influenza vaccines. Sixty-nine percent of children 6 months-18 years of age in Stockholm County received at least one dose of Pandemrix during the 2009 pandemic. We studied the effectiveness of the vaccine during the influenza seasons 2010-2011 and 2012-2013 in children hospitalized with virologically confirmed influenza. The season 2011-2012 was not included, since influenza A(H3N2) was the predominant circulating strain. METHODS: In a retrospective case-control study using a modified test-negative design we compared the percentage vaccinated with Pandemrix among children diagnosed with influenza A(H1N1)pdm09 (cases), with that of those diagnosed with influenza A(H3N2) or influenza B (controls) during the two seasons. We excluded children born after July 1, 2009, since only children who were 6 months of age or older received the pandemic vaccine in October-December 2009. RESULTS: During the 2010-2011 season, 3/16 (19%) of children diagnosed with influenza A(H1N1)pdm09, vs. 32/41 (78%) of those with influenza A(H3N2) or influenza B had been vaccinated with Pandemrix in 2009. The odds ratio, after adjustment for sex, age and underlying diseases, for becoming a case when vaccinated with Pandemrix was 0.083 (95%CI 0.014, 0.36), corresponding to a VE of 91.7%. During the season 2012-2013, there was no difference between the two groups; 59% of children diagnosed with influenza A(H3N2)/B and 60% of those with influenza A(H1N1)pdm09 had been vaccinated with Pandemrix in 2009. CONCLUSION: The AS03 adjuvanted monovalent influenza A(H1N1) pdm09 vaccine (Pandemrix) was effective in preventing hospital admission for influenza A(H1N1)pdm09 in children during at least two seasons.
BACKGROUND: Immunological studies have indicated that the effectiveness of AS03 adjuvanted monovalent influenza A(H1N1)pdm09 vaccine (Pandemrix) may be of longer duration than what is seen for non-adjuvanted seasonal influenza vaccines. Sixty-nine percent of children 6 months-18 years of age in Stockholm County received at least one dose of Pandemrix during the 2009 pandemic. We studied the effectiveness of the vaccine during the influenza seasons 2010-2011 and 2012-2013 in children hospitalized with virologically confirmed influenza. The season 2011-2012 was not included, since influenza A(H3N2) was the predominant circulating strain. METHODS: In a retrospective case-control study using a modified test-negative design we compared the percentage vaccinated with Pandemrix among children diagnosed with influenza A(H1N1)pdm09 (cases), with that of those diagnosed with influenza A(H3N2) or influenza B (controls) during the two seasons. We excluded children born after July 1, 2009, since only children who were 6 months of age or older received the pandemic vaccine in October-December 2009. RESULTS: During the 2010-2011 season, 3/16 (19%) of children diagnosed with influenza A(H1N1)pdm09, vs. 32/41 (78%) of those with influenza A(H3N2) or influenza B had been vaccinated with Pandemrix in 2009. The odds ratio, after adjustment for sex, age and underlying diseases, for becoming a case when vaccinated with Pandemrix was 0.083 (95%CI 0.014, 0.36), corresponding to a VE of 91.7%. During the season 2012-2013, there was no difference between the two groups; 59% of children diagnosed with influenza A(H3N2)/B and 60% of those with influenza A(H1N1)pdm09 had been vaccinated with Pandemrix in 2009. CONCLUSION: The AS03 adjuvanted monovalent influenza A(H1N1) pdm09 vaccine (Pandemrix) was effective in preventing hospital admission for influenza A(H1N1)pdm09 in children during at least two seasons.
Authors: Huiying Chua; Shuo Feng; Joseph A Lewnard; Sheena G Sullivan; Christopher C Blyth; Marc Lipsitch; Benjamin J Cowling Journal: Epidemiology Date: 2020-01 Impact factor: 4.822
Authors: Amanda L Wilkins; Dmitri Kazmin; Giorgio Napolitani; Elizabeth A Clutterbuck; Bali Pulendran; Claire-Anne Siegrist; Andrew J Pollard Journal: Front Immunol Date: 2017-12-13 Impact factor: 7.561