If the number is high, this increases the likelihood that an infected person will infect other people because they are more likely to shed more viral particles than someone with a lower figure. In the case of COVID-19 the most infectious method of transmitting viral particles is by droplets from the nose or mouth.
In medicine viral load is measured by parts per ml in either blood or plasma. Viral load is also known as viral burden, which is different to body burden.
This is the average number of virus particles any individual needs to be exposed to before they become unwell from the virus. In the case of the flu virus for example, the infectious dose is relatively low before someone will become ill; this is why it is described as highly infectious. Scientists researching the coronavirus, COVID-19 don’t know yet how big a dose someone needs to be exposed to before they become ill, but it’s likely to be very low because of the rapid spread of the disease seen around the globe.
In diseases such as influenza a higher viral load has been associated with the infected person experiencing worse symptoms. In the case of the coronavirus COVID-19 it’s not yet clear whether a person carrying a higher viral load is more likely to become more unwell than someone with a low viral load.
Scientists around the world are reporting varied findings in the case of COVID-19; in Italy they’ve found a high correlation between high viral load and severity of the illness, but other studies in China have reported no clear association between viral load and severity of illness. It is still early days in the study of this disease and much more research is needed. We will report updates in our Health Hub (link)
According to the World Health Organisation, in the case of Covid-19 the infectious pathogen is found in the upper airway. The viral load seems to be peaking just as someone begins to feel unwell so it can be a short period of time between infection and showing first symptoms. Not everyone displays symptoms however and research is ongoing about why many people are asymptomatic.
COVID-19 is different to other coronaviruses when pathogens are clustered lower down in the respiratory tract, such as the SARS virus. In this case someone may carry the virus for a longer period of time before they become unwell.
This term describes the mechanic whereby the body has to reach a certain threshold above which symptoms might occur. The threshold is not fixed and can be lowered by stress, infection and general factors such as lack of sleep. To reach the threshold, the effects are cumulative as the body interacts with environmental agents. Once the threshold is reached, symptoms will be produced, and this is called the load phenomenon.
Loads that contribute to reaching a threshold include things like indoor and outdoor air pollution, impure water and food. If a person is sensitive to certain foods and chemicals in the environment, the threshold is swiftly reached, and symptoms are more likely to be seen. However, if a person has few stresses, plenty of exercises, ample sleep and no infection, despite encountering items to which they are sensitive, the threshold may not be reached. This explains why exercise is so important for a healthy immune system.
If the body is continuously being overburdened by environmental, lifestyle factors, common foods such as wheat, milk, sugar, eggs and potato, this could mask other symptoms. Chronic symptoms may fluctuate on and off depending upon the body’s total load.
Body burden specifically refers to the accumulation of synthetic chemicals that are stored in the human body at detectable levels. Chemicals in the environmental enter our bodies in food, drinks, ambient and polluted air, and everyday products that touch our skin. These chemicals tend to leave the body very slowly, and the body stores them in body tissue, especially fat cells.
Learn more about endocrine disruptors. Read more