By : Borzoo Salek,MD
The Scientific Manager
Investigator , Senior ,& Executive Manager Of Knowledgebased Projects In Virology Domain
SARS-CoV-2 is here to stay. It’s worth asking the question: What will the virus look like in Next years? Pathogens are rarely fully eradicated from the planet. In fact, this feat has only been achieved with smallpox and rinderpest (a viral disease that afflicts cows). SARS-CoV-2 will not break the trend: The virus is here to stay.
But firstly we have to ask a question that ” How long have coronaviruses existed?”
▪ How long have coronaviruses existed?
The most recent common ancestor (MRCA) of all coronaviruses is estimated to have existed as recently as 8000 BCE, although some models place the common ancestor as far back as 55 million years or more, implying long term coevolution with bat and avian species.1
The most recent common ancestor of the alphacoronavirus line has been placed at about 2400 BCE, of the betacoronavirus line at 3300 BCE, of the gammacoronavirus line at 2800 BCE, and the deltacoronavirus line at about 3000 BCE. Bats and birds, as warm-blooded flying vertebrates, are an ideal natural reservoir for the coronavirus gene pool (with bats the reservoir for alphacoronaviruses and betacoronavirus – and birds the reservoir for gammacoronaviruses and deltacoronaviruses). The large number and global range of bat and avian species that host viruses have enabled extensive evolution and dissemination of coronaviruses.2
Many human coronaviruses have their origin in bats.3 The human coronavirus NL63 shared a common ancestor with a bat coronavirus (ARCoV.2) between 1190 and 1449 CE.4
▪ When Was Scientists identified a human coronavirus For The First Time? ; Coronavirus Evolution
Scientists first identified a human coronavirus in 1965. It caused a common cold. Later that decade, researchers found a group of similar human and animal viruses and named them after their crown-like appearance.
Seven coronaviruses can infect humans. The one that causes SARS emerged in southern China in 2002 and quickly spread to 28 other countries. More than 8,000 people were infected by July 2003, and 774 died. A small outbreak in 2004 involved only four more cases. This coronavirus causes fever, headache, and respiratory problems such as cough and shortness of breath.
MERS started in Saudi Arabia in 2012. Almost all of the nearly 2,500 cases have been in people who live in or travel to the Middle East. This coronavirus is less contagious than its SARS cousin but more deadly, killing 858 people. It has the same respiratory symptoms but can also cause kidney failure.
The virus that causes COVID-19 is new, but other coronaviruses have been around for decades. The first description of a coronavirus as a human pathogen occurred more than half a century ago at The University of Chicago. This isn’t just an interesting historical footnote. As the COVID-19 pandemic continues to affect the global community and scientific researchers work to develop treatments and ultimately, a vaccine, they are building on knowledge pulled from research on other human coronaviruses (HCoVs) that are genetically related.
In 1962, University of Chicago researchers isolated a previously unidentified RNA virus during a study of upper respiratory infections among medical students. The researchers characterized this new virus and named it 229E (later HCoV-229E). The initial work, published in 1966 in Experimental Biology and Medicine, and the 1967 follow-up study in the Journal of Virology were able to give initial information on the growth times, virus size and images of the virus particle infection within human cells cultured in a dish. Researchers showed that this new virus did not react to antisera, blood serum containing antibodies, for any major known viruses, such as influenza strains, measles or mumps.5
▪ When Will the Pandemic Really End ?
As we near the 2-year mark for the ongoing COVID-19 crisis, experts are offering predictions on how the situation might change going into 2022. Dr. Anthony Fauci said in an interview with CNN that we could start having some control over the pandemic come spring6 , while Moderna’s CEO, Stéphane Bancel, thinks the pandemic could be over in a year.7 And, according to recent mathematical modeling, the Delta variant is peaking, and cases should steadily decline through the winter.8
“I think at this point, it’s hard to predict anything,” Dr. Vidya Mony, pediatric infectious diseases specialist at Santa Clara Valley Medical Center in San Jose, California. She also pointed out it’s “quite optimistic” to believe the pandemic will be over in a year, and emphasized the nature of the pandemic requires global solutions.9
“By definition, this is an infectious disease that is spread worldwide,” Mony said. “Unless we are able to vaccinate the entire world, it is quite possible that we will continue to have variants and continue to have transmission.” According to Mony, the United States may have dropped pandemic restrictions too soon. “Though we knew about the Delta variant and its deleterious effects from India, the U.S. started opening up in June,” she said. “Which, as we all know, in retrospect was not the greatest recommendation.”
There’s evidence that natural immunity is at least as protective as immunity produced by vaccination, and that a single vaccine dose can further bolster natural immunity. These facts should be taken into account when national and international vaccination policies are developed. Providing an optional booster dose to recovered COVID patients who choose to take it would expand the pool of vaccine doses available to immunize vulnerable individuals who have not yet become ill.10
▪ After the pandemic: perspectives on the future trajectory of COVID-19
There is a realistic expectation that the global effort in vaccination will bring the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) under control.
Nonetheless, uncertainties remain about the type of long-term association that the virus will establish with the human population and, in particular, whether coronavirus disease 2019 (COVID-19) will become an endemic disease.
Although the trajectory is difficult to predict, the conditions, concepts and variables that influence this transition can be anticipated. Persistence of SARS-CoV-2 as an endemic virus, perhaps with seasonal epidemic peaks, may be fuelled by pockets of susceptible individuals and waning immunity after infection or vaccination, changes in the virus through antigenic drift that diminish protection and re-entries from zoonotic reservoirs.
Early in 2020, the world observed a sharp increase in the reported number of SARS-CoV-2 infections. The rapid accumulation of cases contrasted not only with the historical numbers of the SARS-CoV outbreak in 2003, but also with the numbers from the pandemic in 2009 caused by influenza H1N1, with the caveat that perhaps cases of an H1N1 infections were underdiagnosed (Fig. 1). The pattern and impact of the pandemic revealed flaws in the worldwide response to the infection—some local of which were in nature, whereas others were more systematic across many different countries.
With the ongoing deployment of several highly effective SARS-CoV-2 vaccines in many countries, there is an expectation that this virus will disappear. However, two reasons temper our hope in reaching this conclusion: patchy vaccine coverage due to disparities in global access to vaccines and vaccine hesitancy, and vaccines may not always block virus transmission (despite reducing the burden of disease).
In addition, although mass vaccine deployment may signal the end of the pandemic, the end of the pandemic does not necessarily equate to the end of SARS-CoV-2.
▪ Refrences :
- Wertheim JO, Chu DK, Peiris JS, Kosakovsky Pond SL, Poon LL (June 2013). “A case for the ancient origin of coronaviruses”. Journal of Virology.
- Woo PC, Lau SK, Lam CS, Lau CC, Tsang AK, Lau JH, et al. (April 2012). “Discovery of seven novel mammalian and avian coronaviruses in the genus deltacoronavirus supports bat coronaviruses as the gene source of alphacoronavirus and betacoronavirus and avian coronaviruses as the gene source of gammacoronavirus and deltacoronavirus”. Journal of Virology.
- Forni D, Cagliani R, Clerici M, Sironi M (January 2017). “Molecular Evolution of Human Coronavirus Genomes”. Trends in Microbiology.
- Huynh J, Li S, Yount B, Smith A, Sturges L, Olsen JC, et al. (December 2012). “Evidence supporting a zoonotic origin of human coronavirus strain NL63”. Journal of Virology.
By : Borzoo Salek,MD
Dr. Borzoo Salek has been a researcher, senior consultant and executive director of many health projects and comprehensive projects for more than three decades in the areas of infection control, burns, cancer, cell therapy and stem cells . The present article is an topics of this, which is presented