Developing mucosal vaccines for respiratory viruses

Vaccines that provide long-lasting protection against influenza, coronaviruses and respiratory syncytial virus (RSV) have proved exceptionally difficult to develop. Researchers from the National Institute of Allergy and Infectious Diseases (NIAID), part of the NIH, explore the challenges and outline approaches to improved vaccines.

Illustration shows 3D renditions of three dangerous respiratory viruses. Photo: NIAID

Anthony S. Fauci, M.D., former NIAID director, is an author along with Jeffery K. Taubenberger, M.D., Ph.D., and David M. Morens, M.D.

Unlike the respiratory viruses that cause measles, mumps and rubella—for which vaccination or recovery from illness provides decades-long protection against future infection—flu, RSV, SARS-CoV-2 and “common cold” coronaviruses share several characteristics that enable them to cause repeated re-infections.

These include very short incubation periods, rapid host-to-host transmission and replication in the nasal mucosa rather than throughout the body.

This last feature—non-systemic replication—means these viruses do not stimulate the full force of the adaptive immune response, which typically takes a week or more to mount.

A next generation of improved vaccines for mucosa-replicating viruses will require advances in understanding on several fronts, the authors say.

For instance, more must be learned about interactions between flu viruses, coronaviruses and RSV and the components of the immune response that operate largely or exclusively in the upper respiratory system.

Over time, these interactions have evolved and led to “immune tolerance,” wherein the human host tolerates transient, limited infections by viruses that are generally non-lethal to avoid the destructive consequences of an all-out immune system attack.

The authors note that mucosal immunization appears to be an optimal route of vaccination for the viruses of interest, when feasible.

However, to develop useful mucosal vaccines, significant knowledge gaps must be filled including finding ideal vaccine formulations; determining dosage size, frequency and timing; and developing techniques for overcoming immune tolerance.

The NIAID authors urge fellow researchers to “think outside the box” to make strides toward vaccines that can elicit durable protection against these viruses of considerable public health impact.

They conclude, “we are excited and invigorated that many investigators…are rethinking, from the ground up, all of our past assumptions and approaches to preventing important respiratory viral diseases and working to find bold new paths forward.” (National Institutes of Health)

YOU MAY ALSO LIKE

Experimental Cat Allergy Therapy Gives More Effective Relief

Researchers are testing a new way to treat people with allergies. The method uses regular allergy shots plus a lab-made molecule.

Keeping indoor humidity levels at a "sweet spot" may reduce spread of COVID-19

Study links very dry and very humid indoor environments with worse COVID-19 outcome.

New 3-D model offers insights into the role of glucose in a deadly kidney disease

A research team has developed a new approach to better understand the biology of polycystic kidney disease (PKD), an often-life-threatening genetic disorder that affects millions worldwide.

Study links specific outdoor air pollutants to asthma attacks in urban children

Moderate levels of two outdoor air pollutants, ozone and fine particulate matter, are associated with non-viral asthma attacks in children and adolescents who live in low-income urban areas, a study has found.

Technique for tracking resistant cancer cells could lead to new treatments for relapsing breast cancer patients

Cambridge scientists have managed to identify and kill those breast cancer cells that evade standard treatments in a study in mice. The approach is a step towards the development of new treatments to prevent relapse in patients.

‘Programmable molecular scissors’ could help fight COVID-19 infection

Cambridge scientists have used synthetic biology to create artificial enzymes programmed to target the genetic code of SARS-CoV-2 and destroy the virus, an approach that could be used to develop a new generation of antiviral drugs.