Professor Helen McShane FMedSci, Professor of Vaccinology at the University of Oxford, explores the power of vaccines to save lives, and why continued research and public trust remain essential.

Smallpox, the only human infectious disease that has been eradicated, was done so through effective vaccination. We are tantalisingly close to eliminating polio in the same way.

Vaccines are arguably the most cost-effective health intervention ever developed, saving an estimated 3.5 to 5 million lives every year, according to the World Health Organization. Its Expanded Programme on Immunization, which provides routine vaccines for infants and children, is responsible for around 3 million lives saved, much of which is due to measles vaccination.  

However, not all vaccines are so effective. One of the oldest, BCG, is the only licensed vaccine against tuberculosis (TB). It provides high levels of protection against disseminated and brain tuberculosis when administered to newborn babies but does not prevent lung disease in adults. Better vaccines for TB and for other complex pathogens such as HIV, are urgently needed.

A decade of extraordinary progress

Over the last decade, there has been a huge amount of progress in vaccine research and development. After decades of research, we now have two licensed vaccines against malaria, previously considered ‘too difficult’. Highly effective vaccines against human papilloma virus (HPV) can prevent cervical and other HPV-associated cancers.  

The COVID-19 pandemic also demonstrated the unprecedented speed at which vaccines can be developed, with two licensed vaccines less than a year after the genetic code for SARS CoV-2 was known. One used the then-novel mRNA technology for the first time.  

While mRNA is unlikely to be a magic bullet for every disease, recent evidence suggests this technology may also be effective against some cancers.  

As we understand more about how vaccines work, it is becoming clear that some vaccines may have so called ‘non-specific’ or off target effects. For example, BCG vaccination given to newborn babies can prevent severe non-tuberculous infections in infancy, and vaccines against shingles and RSV may be associated with a lower risk of dementia. More research is needed to understand these effects.  

Looking to the next generation of vaccines

There are many other pathogens for which effective or better vaccines are needed. A universal influenza vaccine, for example, is urgently needed to prevent the need to develop a new vaccine each year to match circulating strains.  

Emerging viruses with pandemic potential, such as Ebola, also require us to be able to rapidly adapt existing vaccine infrastructure, nationally and internationally, and in academia and industry.  

Promising areas of research include technologies such as mRNA, more effective and better tolerated adjuvants, and new ways of delivering vaccines. Researchers are testing delivery directly to the respiratory tract through nasal sprays or inhalers, with the aim of stimulating immunity at the point where the pathogen enters the body.  Improvements in manufacturing could also help to reduce costs.  

Cause for optimism, but not complacency

Overall, there is enormous cause for optimism, for vaccines against infectious diseases and potentially beyond. Vaccines are among the safest interventions used in medicine and undergo rigorous testing and safety monitoring. They have enormous and long-lasting benefits for individuals and public health.  

Yet globally, confidence in vaccines is not universal. Alongside continued investment in vaccine research and development, we need public engagement and education to understand and address vaccine hesitancy.  

We must ensure that people who need vaccines are ready and willing to use them when they become available, and that effective vaccines are universally available. An important lesson from the recent pandemic is that an infection anywhere can easily become a threat everywhere. 

There is much cause for optimism, but no room for complacency. 

 

 

As part of our ongoing work to tackle health misinformation and improve public trust in medical sciences, we have partnered with the Royal Society to produce a vaccines Q&A answering common questions about vaccines with insights from experts and patient and public contributors.

Related content