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The influence of climate and weather on COVID-19

Publication Date: 
Tuesday, June 30, 2020

The Department of Science and Innovation has formed a team of leading South African environmental scientists from a range of institutions to consider the environmental aspects of COVID-19. Researchers of the COVID-19 Environmental Reference Group look at weather, climate and air pollution effects to advise the epidemiological modelling group of the National Institute of Communicable Diseases and other modelling groups.

COVID-19 in the South African winter

Contact Person

Dr Neville Sweijd

nsweijd@access.ac.za

The Department of Science and Innovation has formed a team of leading South African environmental scientists from a range of institutions to consider the environmental aspects of COVID-19. Researchers of the COVID-19 Environmental Reference Group look at weather, climate and air pollution effects to advise the epidemiological modelling group of the National Institute of Communicable Diseases and other modelling groups.

COVID-19 in the South African winter

The influence of the southern hemisphere winter season on the COVID-19 epidemic in South Africa is unknown and is a topic of some speculation in the media. It is clear that the epidemic will peak here in mid-winter – is that a coincidence?

“The months between April and September are usually associated with the influenza season, but the seasonal prevalence of SARS-CoV-2, the organism responsible for the COVID-19 pandemic, is still speculative. This is because it is a novel virus, that has only been circulating for around six months, and the information that is available regarding the environmental influences on the disease comes mostly from countries in the northern hemisphere,” says Dr Neville Sweijd, Director of the Alliance for Collaboration on Climate and Earth Systems Science, a research programme by the CSIR and the National Research Foundation. 

He says that there are now more than 100 studies that explore the effects of environmental variables on the virus in some way. Many of these are pre-prints that have not yet been peer-reviewed, which is a fundamental requirement for full scientific acceptance. Learning can also be gleaned from laboratory studies on SARS-CoV-2 and similar viruses that have spread globally in the past, such as those responsible for Severe Accute Respiratory Syndrome, (SARS) and Middle East Respiratory Syndrome (MERS).There are several other ‘endemic’ human coronaviruses that cause the common cold and which have a seasonal prevalence.

The COVID-19 Environmental Reference Group (CERG) is investigating how this information translates into the South African experience of the pandemic. Preliminary findings, based on historical average winter conditions, are that as South Africa heads into winter, the portion of the SARS-CoV-2 transmission risk which is attributable to climate, will rise due to falling temperatures and humidity in most of the country. In contrast, warmer conditions should result in a marginal decreasing effect on transmission rates in the northern hemisphere as it emerges from winter. With this in mind, it is likely that the late summer onset could have delayed the timing of the peak of the disease.

e-Symposium on the environmental drivers and seasonality of the pandemic

How will the COVID-19 epidemic manifest over the next few years, at least until an effective vaccine or treatment is widely available? Will SARS-CoV-2 and its variants become one of the family of common viruses with a seasonal prevalence? What is the likelihood of a ‘second wave’ in the winter of 2021? To evaluate this possibility, CERG has participated in global discussions with colleagues in both the northern and southern hemispheres who are considering the same questions. CERG is also working with experts internationally to share data and approaches to the analysis of the environmental influences on the pandemic. CERG will commence with an analysis of the South African situation once sufficient data are available. Under the auspices of the World Metrological Organisation, and together with a set of international partners, CERG has initiated a virtual international symposium to assess what has been learned and what is understood, and can be reliably predicted about the role of environmental variables’ influence on the trajectory of the COVID-19 epidemic from a global, hemispheric, regional and local perspective. The symposium will take place from 4 to 8 August 2020. The outcome of the conference will include a synthesis of the information presented and recommendations for further research and operational responses at global to local scales.

Enquiries:

Professor Francois Engelbrecht
Email: Francois.Engelbrecht@wits.ac.za