Stellenbosch University: Study says, Covid-19 impact could have been less devastating if populations were healthier

Aside from vaccination, focussed public health efforts to target obesity could be a safeguard in a potential future novel viral pandemic, according to frontline Covid-19 doctors from Stellenbosch University (SU) and the University of Cape Town (UCT).

They recently published a research article that looked at Covid-19 outcomes in a population with a high prevalence of HIV and TB, and the research showed that being overweight or obese was significantly associated with dying from Covid-19 in this group.

According to Dr Arifa Parker, first author of the study titled “Clinical features and outcomes of Covid-19 admissions in a population with a high prevalence of HIV and tuberculosis: a multicentre cohort study”, the impact of the Covid-19 pandemic may not have been so devastating if the global population had been in better health. The study was published in the journal BMC Infectious Diseases.

Parker, an infectious diseases specialist at Tygerberg Hospital and the Division of General Internal Medicine at SU’s Faculty of Medicine and Health Sciences (FMHS), emphasised the link between obesity and increased severity of infections such as Covid-19, and other infections such as influenza.

Parker said the study was started early in the Covid-19 pandemic as a collaborative effort between frontline doctors at SU and UCT. “Many questions regarding the impact of the pandemic on patients with HIV and TB were unanswered, and we aimed to share our knowledge and learn from our experiences to better manage our patients.”

The main aim of the study was to describe the clinical features and outcomes of patients admitted to hospital with Covid-19. The researchers specifically looked at communicable diseases (HIV and TB), and also non-communicable diseases or lifestyle diseases (hypertension, diabetes and obesity).

The study combines data on the clinical features and outcomes of Covid‑19 hospital admissions in a population with a high prevalence of HIV and tuberculosis. The 1 434 patients involved in the study, of whom 270 were living with HIV, were admitted to three centres (Tygerberg Hospital, Groote Schuur Hospital and Khayelitsha District Hospital).

Parker explained the significance of the findings of the study: “Prior to the availability of vaccines, we found in our setting with high background rates of HIV and TB that being overweight or obese was significantly associated with dying from Covid-19. This emphasises the need for public health interventions in this patient population.”

Explaining the potential reasons for the link between Covid-19 severity and obesity, Parker said fat cells (adipocytes) have the same receptors that the SARS-CoV-2 virus is able to bind to. “These receptors are overexpressed in obesity. The adipocyte may therefore be a reservoir for the virus, resulting in an increased viral load. People who are overweight also have impaired immunity, which may cause the cytokine release syndrome seen in severe Covid-19 cases.”

Regarding their findings on the role of HIV and TB in Covid-19 mortality rates, she said interestingly enough HIV and TB were not specifically associated with increased Covid-19 mortality in this study. “The bulk of HIV-positive patients admitted with Covid-19 were well controlled on antiretroviral treatment (79%), which may have been protective. However, we also found that patients with HIV and Covid-19 were more likely to also be co-infected with TB, resulting in increased death in this sub-population.”

Parker emphasised that public health measures are urgently needed to prevent and optimise treatment for TB, specifically in people with HIV. “There are still unnecessary deaths from TB, which is entirely preventable and treatable. We need better TB drugs and less toxic regimens.”

According to Prof Helmuth Reuter, Executive Head of the FMHS’ Department of Medicine, the study’s findings emphasise the importance of public health interventions to curb obesity to minimise the risk of severe illness and death. “These patient groups should be prioritised in Covid-19 public health responses, including vaccine allocation.”

Reuter added that the study is very special in that it points toward the important intersection of communicable and lifestyle diseases.

Parker said the main lesson from this study is that focussed public health efforts to target obesity are urgently required. “If we had a healthier global population, the impact of the Covid-19 pandemic may not have been so devastating. This is one lesson we can learn to safeguard our population in a potential future new viral pandemic.”

Dr Ayanda T. Mnguni (SU) and Prof Sean Wasserman (UCT) are joint last authors of this publication, which has been dedicated to the late Prof Birhanu T. Ayele, former FMHS academic, researcher, consultant, and mentor, and all the patients and their families who were affected by Covid-19.