scholarly journals Lessons from History: Methodological Problems arising from Comparing the Influenza A (H1N1) Pandemic 2009-10 to Seasonal Influenza 2010-2019 at the United States

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
James A Koziol ◽  
Jan E Schnitzer
Keyword(s):  
United States ◽  
Influenza A ◽  
H1n1 Influenza ◽  
The United States ◽  
Cross Reactivity ◽  
Influenza Viruses ◽  
Vaccination Programs ◽  
Influenza A H1n1 ◽  
Pandemic Flu ◽  
Novel H1n1 Influenza

Pandemics of human influenza are when influenza viruses that have little or no immunity become capable of transmitting from one person to another. A novel H1N1 influenza virus was discovered in children in the southwest United States in April 2009. Retroactively, it was shown that these cases were the result of an ongoing epidemic in Mexico. A number of national vaccination programs were established in response to the pandemic. Surprisingly early clinical trials data from humans have shown that one dose of nonadjuvanted pandemic flu A (H1N1) 2009 monovalent, inactivated vaccine (pMIV), has resulted in a significant seroprotective response. This is despite previous studies showing no cross-reactivity between pandemic and seasonal H1N1 viruses.

scholarly journals Pandemic H1N1 influenza: predicting the course of a pandemic and assessing the efficacy of the planned vaccination programme in the United States

2009 ◽  
Vol 14 (41) ◽  
Author(s):  
S Towers ◽  
Z Feng
Keyword(s):  
United States ◽  
Influenza A ◽  
Influenza Pandemic ◽  
Vaccination Campaign ◽  
H1n1 Influenza ◽  
The United States ◽  
Pandemic H1n1 ◽  
Pandemic H1n1 Influenza ◽  
Influenza A H1n1 ◽  
Control And Prevention

We use data on confirmed cases of pandemic influenza A(H1N1), disseminated by the United States Centers for Disease Control and Prevention(US CDC), to fit the parameters of a seasonally forced Susceptible, Infective, Recovered (SIR) model. We use the resulting model to predict the course of the H1N1 influenza pandemic in autumn 2009, and we assess the efficacy of the planned CDC H1N1 vaccination campaign. The model predicts that there will be a significant wave in autumn, with 63% of the population being infected, and that this wave will peak so early that the planned CDC vaccination campaign will likely not have a large effect on the total number of people ultimately infected by the pandemic H1N1 influenza virus.

scholarly journals Sequential Seasonal H1N1 Influenza Virus Infections Protect Ferrets against Novel 2009 H1N1 Influenza Virus

2012 ◽  
Vol 87 (3) ◽  
pp. 1400-1410 ◽  
Author(s):  
Donald M. Carter ◽  
Chalise E. Bloom ◽  
Eduardo J. M. Nascimento ◽  
Ernesto T. A. Marques ◽  
Jodi K. Craigo ◽  
...  
Keyword(s):  
Influenza Virus ◽  
H1n1 Influenza ◽  
Cross Reactivity ◽  
Influenza Viruses ◽  
The Novel ◽  
Virus Infections ◽  
H1n1 Influenza Virus ◽  
Virus Shedding ◽  
2009 H1n1 ◽  
Novel H1n1 Influenza

ABSTRACTIndividuals <60 years of age had the lowest incidence of infection, with ∼25% of these people having preexisting, cross-reactive antibodies to novel 2009 H1N1 influenza. Many people >60 years old also had preexisting antibodies to novel H1N1. These observations are puzzling because the seasonal H1N1 viruses circulating during the last 60 years were not antigenically similar to novel H1N1. We therefore hypothesized that a sequence of exposures to antigenically different seasonal H1N1 viruses can elicit an antibody response that protects against novel 2009 H1N1. Ferrets were preinfected with seasonal H1N1 viruses and assessed for cross-reactive antibodies to novel H1N1. Serum from infected ferrets was assayed for cross-reactivity to both seasonal and novel 2009 H1N1 strains. These results were compared to those of ferrets that were sequentially infected with H1N1 viruses isolated prior to 1957 or more-recently isolated viruses. Following seroconversion, ferrets were challenged with novel H1N1 influenza virus and assessed for viral titers in the nasal wash, morbidity, and mortality. There was no hemagglutination inhibition (HAI) cross-reactivity in ferrets infected with any single seasonal H1N1 influenza viruses, with limited protection to challenge. However, sequential H1N1 influenza infections reduced the incidence of disease and elicited cross-reactive antibodies to novel H1N1 isolates. The amount and duration of virus shedding and the frequency of transmission following novel H1N1 challenge were reduced. Exposure to multiple seasonal H1N1 influenza viruses, and not to any single H1N1 influenza virus, elicits a breadth of antibodies that neutralize novel H1N1 even though the host was never exposed to the novel H1N1 influenza viruses.

scholarly journals Planning for the Control of Pandemic Influenza A (H1N1) in Los Angeles County and the United States

2011 ◽  
Vol 173 (10) ◽  
pp. 1121-1130 ◽  
Author(s):  
D. L. Chao ◽  
L. Matrajt ◽  
N. E. Basta ◽  
J. D. Sugimoto ◽  
B. Dean ◽  
...  
Keyword(s):  
United States ◽  
Los Angeles ◽  
Pandemic Influenza ◽  
Influenza A ◽  
Los Angeles County ◽  
The United States ◽  
Influenza A H1n1

scholarly journals Cluster analysis of the origins of the new influenza A(H1N1) virus

2009 ◽  
Vol 14 (21) ◽  
Author(s):  
A Solovyov ◽  
G Palacios ◽  
T Briese ◽  
W I Lipkin ◽  
R Rabadan
Keyword(s):  
Cluster Analysis ◽  
Influenza A ◽  
H1n1 Virus ◽  
Swine Influenza ◽  
The United States ◽  
Influenza Viruses ◽  
World Health ◽  
Influenza A H1n1 ◽  
The World ◽  
Health Organization

In March and April 2009, a new strain of influenza A(H1N1) virus has been isolated in Mexico and the United States. Since the initial reports more than 10,000 cases have been reported to the World Health Organization, all around the world. Several hundred isolates have already been sequenced and deposited in public databases. We have studied the genetics of the new strain and identified its closest relatives through a cluster analysis approach. We show that the new virus combines genetic information related to different swine influenza viruses. Segments PB2, PB1, PA, HA, NP and NS are related to swine H1N2 and H3N2 influenza viruses isolated in North America. Segments NA and M are related to swine influenza viruses isolated in Eurasia.

scholarly journals Household Transmission of 2009 Pandemic Influenza A (H1N1) Virus in the United States

2009 ◽  
Vol 361 (27) ◽  
pp. 2619-2627 ◽  
Author(s):  
Simon Cauchemez ◽  
Christl A. Donnelly ◽  
Carrie Reed ◽  
Azra C. Ghani ◽  
Christophe Fraser ◽  
...  
Keyword(s):  
United States ◽  
Pandemic Influenza ◽  
Influenza A ◽  
H1n1 Virus ◽  
The United States ◽  
Household Transmission ◽  
Influenza A H1n1

scholarly journals Epidemiology of 2009 Pandemic Influenza A (H1N1) Deaths in the United States, April-July 2009

2010 ◽  
Vol 52 (Supplement 1) ◽  
pp. S60-S68 ◽  
Author(s):  
A. L. Fowlkes ◽  
P. Arguin ◽  
M. S. Biggerstaff ◽  
J. Gindler ◽  
D. Blau ◽  
...  
Keyword(s):  
United States ◽  
Pandemic Influenza ◽  
Influenza A ◽  
The United States ◽  
Influenza A H1n1

scholarly journals Contemporary Seasonal Influenza A (H1N1) Virus Infection Primes for a More Robust Response To Split Inactivated Pandemic Influenza A (H1N1) Virus Vaccination in Ferrets

2010 ◽  
Vol 17 (12) ◽  
pp. 1998-2006 ◽  
Author(s):  
Ali H. Ellebedy ◽  
Thomas P. Fabrizio ◽  
Ghazi Kayali ◽  
Thomas H. Oguin ◽  
Scott A. Brown ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Pandemic Influenza ◽  
Influenza A ◽  
Seasonal Influenza ◽  
H1n1 Virus ◽  
H1n1 Influenza ◽  
Influenza Viruses ◽  
Inactivated Vaccine ◽  
H1n1 Influenza Virus ◽  
Influenza A H1n1

ABSTRACT Human influenza pandemics occur when influenza viruses to which the population has little or no immunity emerge and acquire the ability to achieve human-to-human transmission. In April 2009, cases of a novel H1N1 influenza virus in children in the southwestern United States were reported. It was retrospectively shown that these cases represented the spread of this virus from an ongoing outbreak in Mexico. The emergence of the pandemic led to a number of national vaccination programs. Surprisingly, early human clinical trial data have shown that a single dose of nonadjuvanted pandemic influenza A (H1N1) 2009 monovalent inactivated vaccine (pMIV) has led to a seroprotective response in a majority of individuals, despite earlier studies showing a lack of cross-reactivity between seasonal and pandemic H1N1 viruses. Here we show that previous exposure to a contemporary seasonal H1N1 influenza virus and to a lesser degree a seasonal influenza virus trivalent inactivated vaccine is able to prime for a higher antibody response after a subsequent dose of pMIV in ferrets. The more protective response was partially dependent on the presence of CD8+ cells. Two doses of pMIV were also able to induce a detectable antibody response that provided protection from subsequent challenge. These data show that previous infection with seasonal H1N1 influenza viruses likely explains the requirement for only a single dose of pMIV in adults and that vaccination campaigns with the current pandemic influenza vaccines should reduce viral burden and disease severity in humans.

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