COVID-19 temperature checks are given to voter registrants before entering Rocket Mortgage Fieldhouse where a voter registration event took place on September 21, 2020 in Cleveland, Ohio. (Photo: AFP)

A study by Chinese researchers has found that the novel coronavirus has much weaker infectivity at high body temperatures, which suggests fever may significantly improve COVID-19 progression and prognosis, Science and Technology Daily reported.

The findings, based on computational and experimental evidence, have been published in the Computational and Structural Biotechnology Journal.

The study was carried out by researchers from institutes including Guangzhou-based Jinan University and Guangzhou Regenerative Medicine and Health Guangdong Laboratory.

Zhang Qiwei, a corresponding author of the paper and professor at the Institute of Pathogenic Microbiology of Jinan University, said the novel coronavirus penetrates human cells by the binding of the viral spike protein and human angiotensin converting enzyme II (ACE2).

The study found the bind between the spike protein of the novel coronavirus and ACE2 weakens considerably under 39 C - 40 C and the number of viruses that infect cells is relatively reduced, he said.

Results of fluorescence quantitative PCR detection in clinical specimens also showed that COVID-19 patients whose temperature is under 38 C have a much higher viral load of novel coronavirus than those with a temperature higher than 38 C, he added.

Therefore, in the early stage of a COVID-19 infection, a higher temperature can slow the speed of the virus infecting human cells, enabling the body more time to mobilize the immune system to defend itself against the virus and thus alleviating symptoms and reducing the mortality rate. In the advanced stage, however, higher temperature can only cause damage to the body because widespread, high levels of infection of the virus has occurred, leading to a severe cytokine storm and complications, he said.

The conclusion is also supported by clinical data from the team led by respiratory expert Zhong Nanshan and a US hospital, according to Zhang Gong, also a corresponding author of the paper and professor at the College of Life Science and Technology of Jinan University.

The clinical data revealed that body temperature in the early stage of infection (when being admitted to hospital) is the only pathologic factor that obviously influences the prognosis. The mortality rate of those who had a high body temperature when being admitted to the hospital is lower, while high body temperature in the advanced stage plays no role in reducing mortality rate, Zhang Gong said.

Analysis of clinical data showed that the novel coronavirus triggers a milder immune system response, which is less inclined to cause fever immediately, helping it maintain greater infectivity and transmissibility.

The research findings suggest that lowering the body temperature of COVID-19 patients in the early stage of infection may contribute to the spread of infection and worsen the condition while transient fever in early stage of COVID-19 may help the treatment and reduce mortality rate.