Today’s Science News will focus on SARS-CoV-2 and climate change; we’ll learn about a new development regarding the acceptance of Covid-19 vaccines, a new development on the origin of the virus and transmission as well as the impact climate change has on pathogens. Lastly, a note on this important topic as well.
Article 1: Study shows increase in COVID-19 vaccine acceptance around the world
SD-Date: 6th July, 2022
Et-Date: 9th July, 2022
ScienceDaily-Summary: „COVID-19 vaccine acceptance increased 3.7% between 2020 and 2021, according to a new study. In a June 2021 survey of over 23,000 individuals across 23 countries, the researchers found that more than three-quarters (75.2%) of respondents reported vaccine acceptance, up from 71.5% one year earlier.“
Method of Research
The study was conducted by researchers from the CUNY Graduate School of Public Health and Health Policy (CUNY SPH), the Barcelona Institute for Global Health (ISGlobal), the Dalhousie University and the University of Calgary.
Over 23,000 individuals across 23 countries participated in the survey from June 2021.
The participants came from the following countries: United States, United Kingdom, Turkey, Sweden, Spain, Singapore, South Korea, South Africa, Russia, Poland, Peru, Nigeria, Mexico, Kenya, Italy, India, Ghana, Germany, France, Ecuador, China, Canada and Brazil.
- No significant correlation between vaccine hesitancy and a country’s Covid-19 case burden and mortality
- Hesitancy most frequently in:
1. Russia (48.4 %)
2. Nigeria (43.0 %)
3. Poland (40.7 %)
- Hesitancy least frequently in:
1. China (2.4 %)
2. United Kingdom (18.8 %)
3. Canada (20.8 %)
- General Acceptance:
75.2 % (increase by 3.7 % compared to one year earlier)
- Support for vaccination targeting international travellers the strongest,
the weakest for requirements for schoolchildren
- The most consistent correlates of hesitancy were vaccine safety and efficacy,
and mistrust in the science and vaccine development
I think it is important to add this quote from the article, given the circumstances:
„Although some countries are currently disengaging from evidence-based COVID-19 control measures, the disease has by no means been controlled or ended as a public health threat. The authors note that for ongoing COVID-19 vaccination campaigns to succeed in improving coverage going forward, substantial challenges remain. These include targeting those reporting lower vaccine confidence with evidence-based information campaigns and greatly expanding vaccine access in low- and middle-income countries.“
Article 2: Studies link COVID-19 to wildlife sales at Chinese market, find alternative scenarios extremely unlikely
SD-Date: 26th July, 2022
Et-Date: 12th August, 2022
ScienceDaily-Summary: „Analyses based on locations and viral sequencing of early COVID-19 cases indicate the pandemic started in Huanan market in Wuhan, China, with live animals being sold at the market as the likely source. Genomic studies revealed that the SARS-Cov-2 virus jumped into humans on at two separate occasions.“
Note: This article consists of two studies: one about the origin of the virus, the other about the genomic studies. Hence you will see Method of Research and Findings twice.
I. Method of Research
Worobey and Kristian Andersen of the Scripps Research Institute in San Diego, California, conducted the research on the origin of the virus. They examined the geographic pattern of Covid-19 cases in the first month of the outbreak, December 2019.
Almost all locations of the 174 Covid-19 cases identified by the World Health Organization had been determined, 155 of them were located in Wuhan*.
In order to rule out any bias in the analysis, the researchers began removing cases from their analyses, going farther in distance from the market as they went, and ran the stats again. Moreover, the data comes from the hospital where the patients were recorded.
*Wuhan is a large city with 10.76 million inhabitants and the capital of Hubei province. According to UNESCO, it is famous for its 3,500 years of cultural history (earliest recorded settlement during the Western Xi Zhou period (1046-771 BCE) to the southeast of Wuchang; it became the capital of the Wu Dynasty during the period of The Three Kingdoms (220-280 BC)) and that „the city is the cradle of urban civilisation in the Yangtze River basin and the oriental tea harbour of the ancient Tea Road“. The link is embedded in the image description.
- The cases were clustered tightly around the Huanan market
- Later cases were widely dispersed across Wuhan
- In January and February 2020, the patters was the opposite:
while in 2019 it all was very close to the Huanan market, the later
cases coincided with areas of the highest population density in Wuhan.
-> confirms that the virus spread from the market and didn’t circulate cryptically
- The findings were the same for the analysis where they ruled out bias
- Samples were taken from market surfaces like floors and animals cages:
positive tested ones were significantly associated with stalls selling live wildlife
- It was confirmed that animals susceptible to SARS-CoV-2 were sold on the market
„Upstream events are still obscure, but our analyses of available evidence clearly suggest that the pandemic arose from initial human infections from animals for sale at the Huanan Seafood Wholesale Market in late November 2019,“ said Kristian Andersen.
II. Method of Research
The second study was co-led by Jonathan Pekar and Joel Wertheim at the University of California, San Diego and Marc Suchard of the University of California Los Angeles, as well as Andersen and Worobey.
By combining epidemic modeling with analyses of the virus’s early evolution based on the earliest sampled genomes, the researchers were able to determine how often the virus may have jumped across species. They used a technique called molecular clock* analysis to establish a framework for the evolution of the SARS-CoV-2 virus lineages.
|*Molecular clocks (source: Understanding Evolution, UC Museum of Paleontology)|
|„When a stretch of DNA does indeed behave like a molecular clock, it becomes a powerful tool for estimating the dates of lineage-splitting events. For example, imagine that a length of DNA found in two species differs by four bases (as shown below) and we know that this entire length of DNA changes at a rate of approximately one base per 25 million years. That means that the two DNA versions differ by 100 million years of evolution and that their common ancestor lived 50 million years ago. Since each lineage experienced its own evolution, the two species must have descended from a common ancestor that lived at least 50 million years ago.“|
Since viruses such as SARS-CoV-2 are very tiny, adaptation through mutations happen more quickly when they reproduce. If you are interested in how viruses evolve, I recommend reading this article: https://viruses.gslc.utah.edu/how-viruses-evolve
An interesting excerpt from said article about recombination: „There is evidence of recombination in SARS-CoV-2, the novel coronavirus that caused the COVID-19 pandemic. SARS-CoV-2 is most similar to a virus from bats—but the part of the virus that binds to a surface receptor on human cells is most similar to a virus from pangolins. This suggests that two different viruses recombined to make a new virus with genetic information from both. That reshuffling event may have made it possible for the virus to then make the jump to people. There’s evidence that this type of gene sharing has happened before, so we should expect it to happen again. A similar receptor-binding protein is found in SARS CoV, the coronavirus that caused the SARS outbreak of 2003.“ (Gene Shuffling: Making New Combinations)
- The pandemic likely arose from at least two separate infections of humans from animals at the Huanan market; one in November 2019 and the other perhaps in December 2019. To quote from the abstract of The molecular epidemiology of multiple zoonotic origins of SARS-CoV-2: „The first zoonotic transmission likely involved lineage B viruses around 18 November 2019 (23 October–8 December), while the separate introduction of lineage A likely occurred within weeks of this event.“
- Initially, there were likely two distinct lineages of SARS-CoV-2 called A and B
- The analysis also suggests that many other animal-to-human transmissions of the virus at the market that failed to manifest in recorded COVID-19 cases
- A singular transaction would be inconsistent with the molecular clock data, as it was suggested in earlier studies. Otherwise the evolution of lineage A would had been in slow motion compared to the lineage B, which „just doesn’t make biological sense“ according to Worobey
„Moving forward, the researchers say scientists and public officials should seek better understanding of the wildlife trade in China and elsewhere and promote more comprehensive testing of live animals sold in markets to lower the risk of future pandemics.“ (ScienceDaily)
Article 3: Impact of climate change on human pathogenic diseases subject of new study by UH researchers
SD-Date: 8th August, 2022
Et-Date: 13th August, 2022
ScienceDaily-Summary: „A comprehensive assessment of scientific literature has uncovered empirical evidence that more than 58% of human diseases caused by pathogens, such as dengue, hepatitis, pneumonia, malaria, Zika and more, have been–at some point–aggravated by climatic hazards.“
Method of Research
A a team of researchers from the University of Hawaii at Manoa combined two authoritative lists of all known infections and pathogenic diseases that have affected humanity in recorded history. They reviewed more than 70,000 scientific papers for empirical examples to find out how each disease is affected by each possible combination of a climatic hazard.
These 10 climate hazards were selected due to their sensitivity to greenhouse gas emissions and are as follows: warming, drought, heatwaves, wildfires, extreme precipitation, floods, storms, sea level rise, ocean biogeochemical change, and land cover change.
- All climatic hazards were found to influence diseases triggered by viruses, bacteria, animals, fungi, protozoans, plants and chromists*
- 58 % (218 out of 375) of the known human pathogenic diseases had been found to be affected by at least one climatic hazard via 1,006 unique pathways
- While a great majority was aggrevated by climatic hazards, 22 % (63 out of 286 diseases) were diminished
- Most diseases that were diminished by one hazard were aggravated by another, sometimes even the same hazard
Other key findings of the study:
- Climatic hazards are bringing pathogens closer to people.
Hazards such as warming and precipitation change the spatial and
temporal expansion of vectors and pathogens (meaning the environmental
changes result in the expansion of vectors like mosquitoes, ticks, fleas and birds).
Said animals were implicated by outbreaks in outbreaks by viruses including dengue, chikungunya, plague, Lyme disease, West Nile virus, Zika, trypanosomiasis, echinococcosis and malaria to name a few.
- Climatic hazards are bringing people closer to pathogens.
The forced displacement and migration of people due to climatic hazards results in the exposure to pathogens as well. Heatwaves have been associated with several waterborne diseases like Vibrio (a kind of bacteria)-associated infections, primary amoebic meningoencephalitis and gastroenteritis.
Storms, floods and sea level rise, on the other hand, favours pathogens like leptospirosis, cryptosporidiosis, Lassa fever, giardiasis, gastroenteritis, Legionnaires‘ diseases and cholera.
- Climatic hazards have enhanced specific aspects of pathogens.
Stagnant water – for example – caused by heavy rainfall, storms and floods improved climate suitability for pathogens. Thus there’s an increasing breedin ground for Mosquitoes and the various pathogens they transmit.
Heatwaves were suggested as natural selective pressure toward „heat resistant“ viruses, as a result of this adoptation the viruses could better cope with the human body’s main defense – fever.
- Climatic hazards have also diminished human capacity to cope with pathogens.
By altering body condition; the additional stress from exposure to hazardous conditions; when people are forced into unsafe conditions; and damaging infrastructure forcing exposure to pathogens and/or reducing access to medical care.
Drought is given as an example for being conducive conducive to poor sanitation responsible for cases of trachoma, chlamydia, cholera, conjunctivitis, Cryptosporidium, diarrheal diseases, dysentery, Escherichia coli, Giardia, Salmonella, scabies and typhoid fever (see East Africa**, where there’s currently a major crisis going on).
*Chromista means „coloured“ and most of them are photosynthetic, although they are not at all closely related to plants or even algae. „Unlike plants, the Chromista have chlorophyll c, and do not store their energy in the form of starch. Also, photosynthetic chromists often carry various pigments in addition to chlorophyll, which are not found in plants. It is these pigments which give them their characteristic brown or golden color.“ (University of California)
** „Oxfam estimates that 13 million people across Ethiopia, Kenya, and Somalia have been displaced in search of water and pasture, just in the first quarter of 2022. Millions of others had to flee their farmlands and homes due to conflicts, especially in northern Ethiopia – where 9.4 million people now need urgent humanitarian aid. East Africa has also suffered from the worst plague of locusts in 70 years. Kenya has suffered a 70 percent drop in crop production and has declared a national disaster with 3.1 million people facing acute hunger. As many as 28 million across the region could face severe hunger if rains do not fall.“ (source: Oxfam, April 8 2022)
Arte, the French-German public broadcaster, also made a report on it. You can find it on their official Youtube channel.
Link to the German report (13 minutes, 14 seconds):
Lastly, I’d like to recommend the scientific article „Biodiversity loss, emerging pathogens and human health risks“ (National Library of Medicine) to anyone who is interested to learn more about it. Pandemics are not like earthquakes or tsunamis, we can implement policies, measures and work on strategies to minimize the danger.
Here a longer excerpt from the article (it was published online on August 13, 2020).
|In a global assessment of biodiversity, the Intergovernmental Science-Policy Platform for Biodiversity and Ecosystem Services (IPBES, (Bridgewater et al. 2019), has called for a transformative change in the human society. We need to realize that habitat destruction, overexploitation and transportation of species, industrial farming, and the ever-increasing volume of worldwide travel (before the crisis, one plane was taking off every second) all destabilize our environment and favour the spread of pathogens. All these factors increase the probability of disease severity both in wildlife as well as in the human population. We need to rethink our relationship with nature and with the world’s poorest, most neglected populations to minimize future catastrophic epidemics. Perhaps the most poignant current example lies in eastern Democratic Republic of Congo (DRC), an area of exceptional biodiversity and ecological value but also protracted human conflict, associated entrenched poverty, endemic infectious disease burden and perpetual threat of emerging infections. The misfortunes of people living in the eastern DRC were largely ignored by the rest of the world until they suffered an Ebola outbreak that threatened all of us:|
“With a population of 80 million, the DRC has more than 4 million displaced and is home to the world’s second largest food crisis with 13 million people food insecure. Since January 2019, there have been outbreaks of cholera (15,331 cases, 287 deaths), measles (161,397 cases, 3,117 deaths) and malaria, the leading cause of death in the DRC, which kills more than 48,000 people every year” (WHO 2019). After decades of chronic and brutal conflict, including dozens of attacks on Ebola response workers, a long-overdue cease-fire was finally brokered that enabled not only Ebola containment but also strengthening of local health systems generally. At the time of writing, the Ebola outbreak in the eastern DRC was still ongoing and remains a Public Health Emergency of International Concern, meaning a persisting pandemic threat to the world at large (WHO 2020). We suggest there is valuable food for thought in the observation that the dangerous lingering tail of this latest Ebola outbreak, the second largest in history, featured alongside the need to protect healthcare workers from COVID-19 in two editorials on the same page of The Lancet (Anonymous 2020a, b).