The evolving history of influenza viruses and influenza vaccines

Abstract

The isolation of influenza virus 80 years ago in 1933 very quickly led to the development of the first generation of live-attenuated vaccines. The first inactivated influenza vaccine was monovalent (influenza A). In 1942, a bivalent vaccine was produced after the discovery of influenza B. It was later discovered that influenza viruses mutated leading to antigenic changes. Since 1973, the WHO has issued annual recommendations for the composition of the influenza vaccine based on results from surveillance systems that identify currently circulating strains. In 1978, the first trivalent vaccine included two influenza A strains and one influenza B strain. Currently, there are two influenza B lineages circulating; in the latest WHO recommendations, it is suggested that a second B strain could be added to give a quadrivalent vaccine. The history of influenza vaccine and the associated technology shows how the vaccine has evolved to match the evolution of influenza viruses.

Keywords::

• influenza virus
• influenza A
• influenza B
• influenza vaccine
• trivalent inactivated influenza vaccine
• influenza vaccine historical review
• influenza
• virus variations

Acknowledgments

The author would like to thank Sandrine Samson (Sanofi Pasteur MSD) for her critical review and useful suggestions. As well as Sanofi Pasteur MSD for providing funding to write this manuscript and Margaret Haugh (MediCom Consult) for translation and editing services.

Financial & competing interests disclosure

Funding was provided by Sanofi Pasteur MSD. The author has no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Margaret Haugh (MediCom Consult) provided translation and editing services, which was funded by Sanofi Pasteur MSD.

Key issues

• • Influenza virus was first isolated 80 years ago in 1933.

• • The first influenza vaccine was a monovalent live-attenuated vaccine, which was used in Russia until recently.

• • In 1940, a second strain of influenza virus was isolated; this was named influenza B and the first strain was named influenza A.

• • During the Second World War, the first inactivated vaccine was produced by the U.S. army and started to be used widely in 1944, particularly for the American troops in Europe and was then extended to civilians in 1945.

• • In 1947, the vaccine was unexpectedly less efficient; it was discovered that the antigenic composition of the circulating virus had changed and antigenic drift was discovered.

• • Two surface proteins, HA and NA, determine the antigenic properties of influenza virus strains.

• • In 1958, a new strain of influenza A with different HA and NA was identified and antigenic shift was discovered; the need for a trivalent vaccine was recognized.

• • Technical advances have made it possible to produce reassortant strains between wild-type viruses (for their antigenic properties) and culture-adapted strains (for their replication properties).

• • Since 1973, the WHO issues recommendations for the composition of influenza vaccines, based on worldwide surveillance systems and the prediction of the most likely strains to be circulating; since 1999, they issued separate recommendations for the northern and southern hemispheres.

• • In 2013, the WHO recommendations included a second influenza B strain allowing countries to decide to recommend a trivalent or a quadrivalent influenza vaccine.