SciCombinator

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Concept: Influenza vaccine

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In the United States, annual vaccination against seasonal influenza is recommended for all persons aged ≥6 months (1). During each influenza season since 2004-05, CDC has estimated the effectiveness of seasonal influenza vaccine to prevent laboratory-confirmed influenza associated with medically attended acute respiratory illness (ARI). This report uses data from 4,562 children and adults enrolled in the U.S. Influenza Vaccine Effectiveness Network (U.S. Flu VE Network) during November 2, 2017-February 3, 2018. During this period, overall adjusted vaccine effectiveness (VE) against influenza A and influenza B virus infection associated with medically attended ARI was 36% (95% confidence interval [CI] = 27%-44%). Most (69%) influenza infections were caused by A(H3N2) viruses. VE was estimated to be 25% (CI = 13% to 36%) against illness caused by influenza A(H3N2) virus, 67% (CI = 54%-76%) against A(H1N1)pdm09 viruses, and 42% (CI = 25%-56%) against influenza B viruses. These early VE estimates underscore the need for ongoing influenza prevention and treatment measures. CDC continues to recommend influenza vaccination because the vaccine can still prevent some infections with currently circulating influenza viruses, which are expected to continue circulating for several weeks. Even with current vaccine effectiveness estimates, vaccination will still prevent influenza illness, including thousands of hospitalizations and deaths. Persons aged ≥6 months who have not yet been vaccinated this season should be vaccinated.

Concepts: Immune system, Infectious disease, Virus, Vaccine, Vaccination, Influenza, Influenza pandemic, Influenza vaccine

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 The 2014-15 influenza season was distinguished by an A(H3N2) epidemic of antigenically-drifted virus and vaccine containing identical components to 2013-14. We report 2014-15 vaccine effectiveness (VE) estimates from Canada and explore contributing agent-host factors.

Concepts: Immune system, Infectious disease, Virus, Vaccine, Vaccination, Influenza, Avian influenza, Influenza vaccine

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Background During the 2009 influenza A (H1N1) pandemic, pregnant women were at risk for severe influenza illness. This concern was complicated by questions about vaccine safety in pregnant women that were raised by anecdotal reports of fetal deaths after vaccination. Methods We explored the safety of influenza vaccination of pregnant women by linking Norwegian national registries and medical consultation data to determine influenza diagnosis, vaccination status, birth outcomes, and background information for pregnant women before, during, and after the pandemic. We used Cox regression models to estimate hazard ratios for fetal death, with the gestational day as the time metric and vaccination and pandemic exposure as time-dependent exposure variables. Results There were 117,347 eligible pregnancies in Norway from 2009 through 2010. Fetal mortality was 4.9 deaths per 1000 births. During the pandemic, 54% of pregnant women in their second or third trimester were vaccinated. Vaccination during pregnancy substantially reduced the risk of an influenza diagnosis (adjusted hazard ratio, 0.30; 95% confidence interval [CI], 0.25 to 0.34). Among pregnant women with a clinical diagnosis of influenza, the risk of fetal death was increased (adjusted hazard ratio, 1.91; 95% CI, 1.07 to 3.41). The risk of fetal death was reduced with vaccination during pregnancy, although this reduction was not significant (adjusted hazard ratio, 0.88; 95% CI, 0.66 to 1.17). Conclusions Pandemic influenza virus infection in pregnancy was associated with an increased risk of fetal death. Vaccination during pregnancy reduced the risk of an influenza diagnosis. Vaccination itself was not associated with increased fetal mortality and may have reduced the risk of influenza-related fetal death during the pandemic. (Funded by the Norwegian Institute of Public Health.).

Concepts: Pregnancy, Childbirth, Embryo, Fetus, Vaccination, Obstetrics, Influenza, Influenza vaccine

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Assessing the mortality impact of the 2009 influenza A H1N1 virus (H1N1pdm09) is essential for optimizing public health responses to future pandemics. The World Health Organization reported 18,631 laboratory-confirmed pandemic deaths, but the total pandemic mortality burden was substantially higher. We estimated the 2009 pandemic mortality burden through statistical modeling of mortality data from multiple countries.

Concepts: Influenza, Swine influenza, Pandemic, Influenza vaccine, World Health Organization, 2009 flu pandemic, Influenza A virus subtype H1N1, Pandemic H1N1/09 virus

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We randomized 115 children to trivalent inactivated influenza vaccine (TIV) or placebo. Over the following 9 months, TIV recipients had an increased risk of virologically-confirmed non-influenza infections (relative risk: 4.40; 95% confidence interval: 1.31-14.8). Being protected against influenza, TIV recipients may lack temporary non-specific immunity that protected against other respiratory viruses.

Concepts: Immune system, Virus, Vaccination, Innate immune system, Influenza, Avian influenza, English-language films, Influenza vaccine

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Concerns have been raised over competing interests (CoI) among academics during the 2009 to 2010 A/H1N1 pandemic. Media reporting can influence public anxiety and demand for pharmaceutical products. We assessed CoI of academics providing media commentary during the early stages of the pandemic.

Concepts: Influenza, Swine influenza, Pandemic, Influenza vaccine, 2009 flu pandemic, Influenza A virus subtype H1N1, Pandemic H1N1/09 virus, H1N1

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Polypeptide vaccines effectively activate human T cells but suffer from poor biological stability, which confines both transport logistics and in vivo therapeutic activity. Synthetic biology has the potential to address these limitations through the generation of highly stable antigenic “mimics” using subunits that do not exist in the natural world. We developed a platform based on D-amino acid combinatorial chemistry and used this platform to reverse engineer a fully artificial CD8+ T cell agonist that mirrored the immunogenicity profile of a native epitope blueprint from influenza virus. This nonnatural peptide was highly stable in human serum and gastric acid, reflecting an intrinsic resistance to physical and enzymatic degradation. In vitro, the synthetic agonist stimulated and expanded an archetypal repertoire of polyfunctional human influenza virus-specific CD8+ T cells. In vivo, specific responses were elicited in naive humanized mice by subcutaneous vaccination, conferring protection from subsequent lethal influenza challenge. Moreover, the synthetic agonist was immunogenic after oral administration. This proof-of-concept study highlights the power of synthetic biology to expand the horizons of vaccine design and therapeutic delivery.

Concepts: Immune system, Protein, Amino acid, Vaccine, Vaccination, Immunology, Influenza, Influenza vaccine

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To the Editor: Avian-origin influenza A (H7N9) viruses emerged as human pathogens in China in 2013 and have caused 137 cases and 45 deaths to date.(1) These viruses have acquired mutations that could facilitate infection in mammals,(2) which could pose a pandemic threat if the viruses become readily transmissible in humans. Vaccines are a key defense against pandemics, but candidate vaccines featuring H7 hemagglutinins (HA) have been poorly immunogenic.(3) We have previously described the development, manufacture, and efficacy in mice of an A/Anhui/1/13 (H7N9) viruslike particle (VLP) vaccine produced in insect cells with the use of recombinant baculovirus. This vaccine . . .

Concepts: Immune system, Microbiology, Vaccine, Vaccination, Influenza, Influenza pandemic, Pandemic, Influenza vaccine

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School-located influenza vaccination (SLIV) programs can substantially enhance the sub-optimal coverage achieved under existing delivery strategies. Randomized SLIV trials have shown these programs reduce laboratory-confirmed influenza among both vaccinated and unvaccinated children. This work explores the effectiveness of a SLIV program in reducing the community risk of influenza and influenza-like illness (ILI) associated emergency care visits.

Concepts: Infectious disease, Virus, Vaccine, Vaccination, Influenza, Program, Influenza vaccine, Influenza-like illness

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