By Francesca Properzi, PhD, Research Manager, Deloitte Centre for Health Solutions
The COVID-19 pandemic continues to have serious and far reaching consequences for the health and wealth of our population. As countries begin to move into the recovery phase, there is an urgent need to learn the lessons from local, national and international responses. A critical feature of the past four months has been an explosion in the scientific data and literature exploring how and why the pandemic has evolved and what impact is it having. This data suggest the virus is highly discriminatory and that in addition to the underlying health and age of individuals, deprivation and population density are crucial causes of higher mortality rates. What is currently less evident are insights on what we could have done to be better prepared and how we can be better prepared next time? This week’s blog provides ‘my take’ on how improving the immune health of vulnerable populations has a pivotal role to play.
What do we know about past pandemics?
In the past century, the world has experienced six pandemics and at least three major epidemics, originating from animal viruses (see Figure 1).1 As the knowledge of serologic and epidemiologic evidence has increased, the risk of transmission of infectious diseases is increasing.2,3 While we can help protect ourselves through hand and other hygiene practices, public health education, social distancing and face-masks, the keystone of virus prevention is vaccination.
Figure 1. In the past century, the world has experienced six pandemics and three major epidemics, all originating from animal viruses4
Cytokine storms, COVID-19 and the importance of a healthy immune system
Before joining Deloitte I spent ten years leading laboratory research into prion diseases and viral mechanisms. One of the lessons I learned was that a significant percentage of the human genome (up to eight per cent) is made up of viral DNA. Some of these viral sequences are important to our physiology and contribute to key mechanisms of cellular communication, including those involved in neurological functions.5,6
Coronaviruses are a group of viruses that cause disease in mammals and birds and a range of respiratory infections in people, ranging from the mild (the common cold) to the lethal (SARS, MERS and now COVID-19).7 While most people’s immune system is usually well equipped to fight these infections, as shown in the 2003 SARS outbreak, they can occasionally trigger more extreme reactions.8 The level of risk in developing an extreme reaction increases dramatically in people with weak immune systems and can lead to a strong physiological overreaction known as a ‘cytokine storm’, in which multiple immune cells are activated resulting in a hyper inflammatory response. This in turn can lead to organ failure, requiring ventilator-assisted care and/or kidney dialysis.9 People who are immunosuppressed or have high levels of cytokines caused by pre-existing conditions or genetic factors, are more at risk of an extreme reaction, including death, from infections.10
Emerging clinical evidence on people who have died with severe COVID-19 disease indicates this is linked to the hyper-production of cytokines.11 Older people and those with pre-existing medical conditions (such as asthma, diabetes, and heart disease) appear to be more vulnerable to becoming severely ill with the virus.12 The Italian Institute of Health’s research on COVID-19 epidemiology, show that more than 90 per cent of deceased patients had at least one of the above comorbidities and more than 80 per cent were over 70 years old.13
Detecting and improving the ‘immune age’ of individuals within a population
The human immune system deteriorates with age. Population-based cross-sectional studies have shown that all types of immune cells are reduced and become less functional in older people. Inflammatory mediators such as cytokines are also increased. However, aging does not affect all immune systems equally with substantial variations related to the impact of comorbidities, genetic and environmental factors.
Recent scientific studies show that it is possible to detect an individual’s ‘immune age’ by using the variability in their immune system responses.14 Today, artificial intelligence (AI) technologies have enabled the development of multi-modal, multi-omics, age-predictors, to identify immune age biomarkers, or ‘clocks’.15 This could in turn lead to the development of precision drugs, known as ‘geroprotectors’, to halt or reverse the impact of ageing and enable older people to respond more effectively to infections.16
Obesity and the increased risk to the immune health of younger population
Low-grade chronic systemic inflammation is common in people with obesity, and is associated with the development of atherosclerosis, type 2 diabetes, and hypertension, well known comorbidities that affect the outcomes of patients with COVID-19. Severe obesity also present a management challenge with regard to ventilation support and vascular access.17 Globally one in three people over 20 and one in six children under 20 are living with obesity, raising concerns that this is increasing the risk that severe cases of COVID-19 disease will shift to younger age groups.18
Immune health protection programmes for diabetes
People with both type-1 and type-2 diabetes (more than 400 million worldwide) are more susceptible to developing many types of infections. When blood sugars are persistently high (hyperglycaemia), the activity of immune cells is reduced or defective. Overall, this can lead to increased severity of viral infections such as COVID-19. Some healthcare providers have shown that by using data platforms and advanced methodologies for population health management (PHM) it is possible to identify, on a real-time basis, type-2 diabetes patients that exceed the evidence-based guidelines for blood glucose control and take timely action.19 With the help of digital technologies, diabetes registries could also help support tailored treatment programmes, including diet, exercise and life-style changes known to have a significant positive impact on immune health.
Population health management can improve immune health and reduce the impact of future novel viral infections
The evidence now available highlights that immune system impairment is a prominent risk factor for COVID-19 other infections, and presents an opportunity to accelerate the move towards a more patient-centric data-driven approach to optimising the health of the population. Our report ‘The transition to integrated care: population health management in England’ demonstrates the benefits that can be realised from a public health management (PHM) approach focused on prevention, early intervention and protecting the immune health of those people that are most at risk of developing severe responses to infections. Moreover, advances in data analytics, machine learning and digital technologies can provide the tools to make PHM a reality, including stratifying the response for specific patient populations. While the COVID-19 pandemic caught many countries unprepared, by improving the immune health of the population, including tackling health inequalities of vulnerable populations, we should be better prepared next time, because there will be a next time.