How age and gender affect flu vaccine effectiveness

Studies have shown that age and sex are important variables in inducing vaccine responses.

The research is dedicated to the development of vaccines against influenza viruses, respiratory syncytial virus and SARS-CoV-2, which affect people’s health the most

Member of the WHO National Influenza Center in Valladolid.

A series of studies must be conducted to improve existing flu vaccines, make them more multifaceted and benefit vulnerable populations. This claim is supported by data from the doctoral dissertation defended by Dr. Laura Sánchez de Prada at the Faculty of Medicine of the University of Valladolid in July this year, which has received international mention in the compilation of publications.

The research supporting this doctoral work has been carried out over the past four years in collaboration with the research group at the WHO National Influenza Center in Valladolid and the Department of Microbiology at the “Icahn del Monte Sinai” Medical Research Institute in New Mexico . Laboratory of Dr. Adolfo García-Sastre, York, USA.

Furthermore, the study was carried out in collaboration with the General Directorate of Public Health of the military government of Castile and León, which has contributed over the years to influenza surveillance efforts in this community through a sentinel surveillance network of previously vaccinated patients. Serological samples from available samples contribute to these scientific efforts.

The main goal is to identify factors that affect the humoral response (the way the immune system defends against infection) after seasonal influenza vaccination, with particular emphasis on determining which of these factors have the greatest influence in inducing a protective response. .

The results obtained in this area of ​​research have been reflected in five original publications indexed in the first quartile by various international journals with an impact factor between 5 and 19 points.

Due to their importance and novelty in this research area, these are the most relevant contributions:

– First, it has been shown that unadjuvanted vaccines (those that do not contain a substance or procedure that binds to or is injected simultaneously with the antigen to make the immune response more effective) produce a greater response to the influenza A(H1N1)pdm09 subtype type, whereas adjuvanted vaccines elicited greater responses to influenza A(H3N2) subtypes in people over 65 years of age (1).

– Second, both age and biological sex were found to be important variables in inducing vaccine responses. Stronger antibody responses to influenza A(H1N1)pdm09 virus were observed in women over 65 years of age than in men of the same age (2).

University Hospital of Valladolid, headquarters of the National Influenza Center.

– Trivalent vaccination (a vaccine that protects against three strains of influenza) that protects against two influenza A subtypes and one influenza B lineage has been shown to generate an antibody response against the influenza B virus in the vaccine, And also against one type of influenza B virus that’s not included, the first one being the strongest. When vaccinated with a vaccine containing only the B/Victoria lineage, people under the age of 65 showed better responses than those over the age of 65 (3).

– Certain parts (epitopes) of the influenza A(H1N1)pdm09 subtype hemagglutinin protein were found to generate more potent antibody responses than other less immunodominant parts. Furthermore, age and the use of adjuvants in these vaccines have been observed to increase the repertoire of responses directed against minor parts of these proteins (4).

– Finally, using laboratory-modified influenza viruses, it was demonstrated that seasonal vaccines can generate antibodies against the hemagglutinin stem region, which is more conserved and therefore less variable, but also produces less antibody responses than blood Lectin heads work. In addition, it has been observed that people of different ages respond differently to the stem, with a stronger reaction in those under the age of 50 (5).

These findings could have clear implications for public health decision-making and future vaccine research, as the data presented show a series of studies that should be followed to improve existing vaccines, make them more multifaceted, and target vaccinations to the most vulnerable crowd.

The research was conducted in collaboration with the laboratory led by Burgos Professor Adolfo García-Sastre, part of the Icahn Institute at Mount Sinai in New York. Dr. Teresa Aydillo Gómez, who works at the center, collaborated on the direction of the thesis with Dr. José María Eiros Bouza, professor of microbiology at the Faculty of Medicine of the University of Valladolid and director of the National Influenza Centre, and its scientific manager, Dr. Iván Sanz Muñoz.

Over the past forty years, the research group from Valladolid has built a comprehensive record in the field of infections caused by viruses. Up until the emergence of SARS-CoV-2, influenza played a major role in this. Published articles are the result of a collaboration between experts in preventive medicine and public health (eg Dr. Castrodeza Sanz), microbiology (Dr. Rojo Rello and Dr. Domínguez-Gil and Dr. Ortiz de Lejarazu).

The results of this study underscore the importance of developing new vaccines or treatments that focus the response on regions of the protein that are more conserved and generate stronger antibody responses, such as the stem and some antigenic surfaces described in hemagglutinin bit.

Furthermore, these results highlight the importance of developing “universal” vaccines that provide longer-lasting protection and target various influenza virus subtypes. In this context, one of the most important challenges lies in the development of vaccines against influenza viruses, respiratory syncytial virus and SARS-CoV-2, which currently have the greatest impact on human health.

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