Well-ventilated indoor spaces and fewer air-conditioned enclosed spaces are the reason for fewer deaths from coronavirus disease (Covid-19) in developing countries in Asia, including India, according to an analysis published in the Asia Pacific Journal. of Public Health.
The virus remains airborne in enclosed spaces, causing repeated exposure and high viral load build-up in the upper respiratory tract, increasing disease severity and mortality, said authors from Delhi and Mangalore.
“People in developing countries tend to spend less time indoors with air conditioning, where the viral load is higher due to lack of ventilation. This could be the reason why fewer deaths were reported in several Asian countries. In fact, the initial increase in cases was reported in European countries, where people could have stayed indoors longer in the winter months of January and February, ”said Dr. Shyam Aggarwal, first author of the study and chair of the department. Professor of Oncology by Sir Ganga Ram, who collaborated with Max Smart Superspeciality Hospital in Delhi and Kasturba Medical College in Mangalore for the article.
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In India, overcrowded housing is causing the spread. “Although not many people spend time in air-conditioned offices in India, the problem here is that several people live very close together in small houses which leads to transmission within families,” he said.
In examining whether airborne transmission of the viral infection is possible, the World Health Organization said in July that “transmission by short-range aerosols, particularly in specific indoor locations, such as crowded and poorly ventilated spaces over a prolonged period of time with infected people cannot be ruled out. “
Clusters of Covid-19 infections have been reported around the world in such inadequately ventilated spaces, such as a cluster of 10 reported cases in people who had eaten in an air-conditioned restaurant in late January in Guangzhou, China.
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Another group of 52 people reported a choir rehearsal in Washington, USA in March. More than 100 cases of Covid-19 date back to a dance and fitness class in South Korea in February. One of the most recent clusters of 27 cases was linked to a coffee shop in South Korea in August.
The doctor says that it is necessary to increase the air exchange in those closed spaces with air conditioning. “To make places that are not sufficiently ventilated and fully air conditioned, the number of air exchange (circulation of outside air in the air conditioning system) must be increased every hour. In some places, there were only five air exchanges every hour once summer started as it puts more pressure on the system and leads to more electricity consumption. This has to be 12 to 15 exchanges per hour, ”said Dr. Aggarwal.
Experts say that existing evidence suggests that poorly ventilated and fully air-conditioned buildings should be avoided, but whether it leads to higher mortality is unknown.
“In a healthcare setting, some procedures lead to aerosolization of bronchial fluids that have a high viral load and have been seen to place people in the areas most at risk of infection. In another building, if an adequate infusion of outdoor air is not guaranteed and some way of killing viral particles is not guaranteed, such as plasma ionization or UV treatment, there may be an increased risk of infection, ”he said. Dr. Neeraj Gupta, professor in the department of pulmonology at Safdarjung Hospital.
“But I don’t think I can explain the disparity in the number of deaths in various countries. Scientists are still trying to figure out the causes of fewer deaths in some places, be it demographics, an environment not conducive to transmission, mutation of the virus to become milder, genetic factors, the use of certain drugs or vaccines like HCQ. and BCG, ”he said.
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