The amount of infectious agents entering the human body is one of the major determinants of whether someone becomes severely ill from an infection or not, experts say.
The experts advise that wearing facemasks is a cost-effective way to reduce the quantity of the Covid-19 virus that one may contract as they blend in the community.
With the prevailing reality of inadequate hospital beds and Intensive Care Units that are functional across the country, experts say the effort one puts to avoid getting sick from Covid-19 could be an escape path in remaining alive.
Dr Henry Kajumbula, a microbiologist at Makerere University College of Health Sciences, who is leading the committee on Covid-19 infection prevention and control at the Ministry of Health, says the above knowledge can be used to combat Covid-19.
“The dose of exposure is one of the main determinants that someone will become sick because of an infection. Even if a person is highly resistant, a high level of exposure will overwhelm the immune system,” he said yesterday.
The experts said when one is wearing a facemask, even if they are exposed to people who are infected, their chance of becoming infected reduced.
Available scientific reports have also demonstrated the effectiveness of limiting the amount of exposure in gastro-intestinal viruses, sexually transmitted diseases and respiratory infections, on one developing a sickness.
Dr Julius Lutwama, a virologist and deputy director of Uganda Virus Research Institute (UVRI), said exposure-disease theory has been known for a number of other diseases.
“Even for contagious diseases like Ebola, it is not just about being next to someone with a virus. It is about getting into contact with the virus and the amount that enters your body,” he said.
Because it is unethical to test the effectiveness of how much exposure will make one get Covid-19 illness, a team of scientists from Hong Kong University tested the hypothesis on hamsters.
The study published on May 30 in a scientific journal Infectious Clinical Diseases, where surgical masks were used to filter the air into their cages indicated that the chance of hamsters getting infected with Covid-19 reduced. If they got infected, they had milder disease.
“Surgical mask partitions for challenged index or naïve hamsters significantly reduced transmission to 25 per cent (6/24).
“The infected naïve hamsters had lower clinical scores, milder histopathological changes, and lower viral expression in respiratory tract tissues,” the researchers wrote.
Dr Kajumbula said “if both parties are wearing masks, the protection will increase to probably 75 per cent.”
Protecting the elderly
Dr Julius Lutwama from Uganda Virus Research Institute (UVRI)asked people to give additional protection to the elderly and other vulnerable groups (those who are immune-suppressed)because they have a higher chance of developing severe disease when exposed.
“Whenever we are interacting with them [the elderly and vulnerable groups], we should always have facemasks to enhance their protection. I have elderly people around my home, I used to find them walking along the road and give them a lift but these days, I don’t do it,” he said.