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SARS-CoV2 and Influenza: A Double Threat

While we fight SARS-CoV-2, we must not turn our back on influenza

As of this writing, the SARS-CoV-2 virus has infected at least 15.5 million people worldwide and resulted in at least 632,000 deaths. While extreme public health measures such as testing, contact tracing, school closures, travel restrictions, stay-at-home orders, social distancing, and compulsory masking, appear to have tamed the spread of the virus in some parts of the world, the pandemic is still growing in a number of highly populated countries including the US and Brazil, and outbreaks are frequent everywhere as countries try to balance the risks of the virus against the very real risks of economic and mental health collapse.

Accordingly, a huge global effort is under way to develop vaccines that will provide widespread immunity against the virus, relieve the burden of COVID-19 morbidity and mortality, and allow communities to return to more sustainable social and economic behaviors.

In the US, a cooperative partnership between the CDC, the FDA, the NIH, BARDA, the DoD, private industry, and other federal agencies—known as Operation Warp Speed (OWS) -- is coordinating a massive effort to develop, test, approve, and deliver a safe and effective vaccine to US citizens by early 2021. Although that is an incredibly aggressive timeline for vaccine development, several candidates have shown promise in early testing and are poised to move into pivotal trials. No matter how long the effort takes, the research being done is sure to advance vaccine science in a paradigm-shifting way.

One danger of this intense focus on taming the SARS-CoV-2 pandemic is the potential that we lose sight of another serious and looming threat to public health: seasonal influenza.

InVitria partners with a number of vaccine manufacturers to provide them with recombinant, animal-free, serum-free, cGMP-compliant components and excipients for cell-based vaccine manufacturing and final vaccine formulation. InVitria's Exbumin is one of the products that is actively included in vaccine platforms. For example, the first FDA and EMA approved Ebola vaccine - ERVEBO produced by Merck utilizes Exbumin in final formulation. We engage in conversation and collaboration with epidemiologists, virologists, and vaccinologists on a daily basis, and the consensus is as clear as it is obvious: we are likely to be battling deadly viral disease on multiple fronts as we head into the fall.

The World Health Organization estimates that 290,000 to 650,000 people die from influenza-related respiratory illness annually; this mortality and the associated morbidity represent their own, enormous burden on global public health.

Ominously, researchers monitoring zoonotic reservoirs for influenza are closely watching a strain of swine flue with human pandemic potential that is increasingly circulating in pigs in China . The variant, dubbed G4, is a blend of viral lineages from birds, swine, and human influenza, with an avian core against which humans have no immunity.

We don’t know if G4 will jump to humans this year. We also don’t yet know whether the burden of seasonal influenza will be dampened or amplified by COVID-19. The severity of influenza this year is a complex and multifactorial equation with many unknown variables including:

  • The virulence of this season’s predominant influenza strains
  • The pandemic potential of this season’s predominant influenza strains
  • The current level of residual/partial immunity to this season’s predominant influenza strains
  • The potential for influenza and SARS-CoV-2 to be co-infective and the resulting effect on the body
  • Potential alterations in susceptibility to each disease caused by the other
  • The effect of global anti-SARS-CoV-2 public health measures—and the changing nature of those measures—on the spread of influenza virus
  • How current strains on the healthcare system and pandemic preparedness will affect the global response to influenza
  • How current advances in SARS-CoV-2 research will translate to advances in influenza prevention and treatment

The lack of a consistent, reliable, and universal vaccine against influenza viruses is a huge problem.

Seasonal influenza is highly adaptive, rapidly circumventing the body’s immune response to infection or vaccination. Current methods for influenza vaccine manufacture, based on production in chicken eggs, are slow and require long manufacturing lead times. More importantly, traditional egg-based production is susceptible to genetic drift, reducing vaccine effectiveness. —this was proven to negatively influence the effectiveness of influenza vaccines in the 2012-2013 and 2014-2015 seasons.

A host of new technologies are on the horizon for vaccine production, and in the long run the dramatic push to find a vaccine against SARS-CoV-2, is likely to improve vaccines for a host of viral diseases including influenza. Regardless, it would be potentially disastrous to shift focus on the 2020-2021 influenza season to the back burner.

Jeanne McAdara Ph.D.

Written by Jeanne McAdara Ph.D.

Dr. McAdara is part of InVitria's medical and scientific communications team. She has been involved in scientific communications for 19 years and is the Principal of Biolexica Health Science Communications. Dr. McAdara earned her Ph.D. in Macromolecular and Cellular Structure and Chemistry from The Scripps Research Institute and was a postdoctoral fellow in the Jonsson Comprehensive Cancer Center, where she studied the biochemical and cellular mechanisms underlying leukemia.