Again at the beginning of the COVID-19 pandemic, case numbers on the continent have been nonetheless modest. However predictions and projections steered the illness was going to chop a swathe via Africa.
In April 2020 the United Nations Financial Fee for Africa sounded the alarm bell:
Anyplace between 300,000 and three.3 million African individuals might lose their lives as a direct results of COVID-19, relying on the intervention measures taken to cease the unfold.
The World Well being Organisation Regional Workplace for Africa forecast that as much as 190,000 individuals might die within the first yr of the pandemic if COVID-19 in Africa was not managed.
Twelve months later, these dire forecasts have, largely, not been realised. By the tip of April 2021 the overall COVID-19 circumstances in Africa numbered 4,431,639, with some 117,934 deaths reported. South Africa alone accounts for round a 3rd of the caseload, however virtually 50% of the deaths. Certainly 117,943 deaths are tragic. However the quantity will not be almost as excessive as predicted by some.
Many possible theories for this comparatively modest outbreak are being floated. One idea factors to Africa’s atypically young population – younger individuals are much less prone to extreme COVID-19 and hospitalisation. One other idea is that African populations might need a genetically linked resistance to the coronavirus. Some suppose the widespread use of pharmaceutical therapies and childhood vaccines corresponding to anti-malarial medicine and the Bacillus Calmette-Guerin childhood vaccine may play an element, and others level to the continent’s decrease inhabitants density.
In our latest paper we discover the potential hyperlinks between SARS-CoV-2 an infection, COVID-19 illness and diet. Extreme malnutrition is essentially the most prevalent cause of immunodeficiency within the creating world.
We centered on malnutrition that results in poor ranges of leptin, corresponding to is seen in protein power malnutrition, a deficiency of dietary protein despite sufficient calorie intake. Protein power malnutrition is a worldwide difficulty, and whereas the situation has decreased in Asia, African nations have reported a continued increase. Leptin is a hormone that’s made within the fats cells of the physique and has a number of roles within the immune system.
Leptin deficiency brought on by malnutrition definitely doesn’t shield an individual from an infection by the coronavirus inflicting COVID-19. However, based mostly on the work of others in molecular drugs and immunology, we propose it’d counteract the hurt brought on by the extreme irritation that happens with COVID-19 illness. In fact, this may not be a cause to calm down efforts to battle any type of malnutrition.
Leptin will increase the physique’s response to inflammatory cytokines – proteins that regulate irritation. Chubby COVID‐19 optimistic sufferers are inclined to have increased leptin ranges. And excessive leptin ranges are related to extreme COVID‐19. Subsequently, the affect of leptin on the immune system and its correlation with COVID-19 progression and severity might additionally make it a priceless biomarker, for predicting affected person outcomes.
Diet, leptin and the immune system
Malnutrition includes undernutrition (losing, stunting, underweight), insufficient nutritional vitamins or minerals, chubby and weight problems. We all know that malnutrition has been linked to adjustments within the immune system – that is particularly so with protein power malnutrition.
The immune system of individuals with a balanced dietary consumption responds to an infection by releasing cytokines. These are signalling molecules that instruct the immune system to assault invading microbes. Mostly, the assault takes the type of inflammation. As soon as the invading microbes are eradicated from the physique, the irritation disappears and the physique returns to regular. This cautious steadiness of activation and deactivation of the inflammatory response is essential for regular functioning of the physique.
As we have discovered over the previous yr, in lots of extreme COVID-19 circumstances the immune system produces a surge of cytokines, often known as a cytokine storm. This causes a protracted hyper-inflammatory response that does extra hurt than good when it assaults the physique’s organs.
In individuals with low leptin levels, corresponding to these with protein power malnutrition, the immune system produces extra anti-inflammatory cytokines and fewer inflammatory ones.
This shift within the immune response in favour of an anti-inflammatory profile would, in idea, counteract the dire penalties of the hyper-inflammatory response usually seen in extreme COVID-19 circumstances, the place the affected person’s organs might be broken.
However it’s additionally potential that this anti-inflammatory response might masks the signs of malnourished individuals contaminated with COVID-19. They may seem to have a gentle to reasonable chilly or flu moderately than COVID-19. Because of this the true variety of COVID-19 infections could possibly be underestimated and will contribute to transmission of the illness as a result of individuals do not know they’re contaminated.
Worldwide lockdowns have highlighted issues around food insecurity. This contains consuming the correct quantity of the fitting vitamins.
Right here we theorise that poor leptin ranges brought on by malnutrition may shield in opposition to extreme COVID-19 and COVID-19-related dying. This could possibly be one more reason we’re seeing decrease than anticipated COVID-19 deaths in Africa.
However even when that is true, we should always not ignore the truth that malnutrition is killing millions and we should always not curb efforts to eradicate meals insecurity globally.