COVID-19, the disease caused by the coronavirus SARS-CoV-2, is deemed to be become a pandemic
When we thought we are spared by the dreadful coronaviruses, like SARS-CoV, here we are again in a pandemonium over a seemingly inevitable pandemic war against minuscule invaders of the same kind. It is as if we are in a global battle — a tussle between the living and the arguably non-living entities at the cellular level. A deadly aggression rages between the immune cells and the virulent coronavirus, SARS-CoV-2.
Early this year, we were jolted by an ominous report about a newly-emerged virus causing a disease as deadly as the other coronavirus outbreaks. The virus, dubbed initially as 2019-nCOV, already made a mark when mass anxiety across the globe spiked upon its unveiling on the news. People began wearing masks when in public for fear of contracting the virus. On February 11, the International Committee on Taxonomy of Viruses (ICTV) gave the virus its official name, SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2). The name implies its semblance and genetic relatedness to SARS-CoV, the coronavirus responsible for the SARS outbreak in 2003. Both SARS-CoV-2 and SARS-CoV belong to the same taxonomic genus, Betacoronavirus, and species (i.e. severe acute respiratory syndrome-related coronavirus). Nevertheless, they are two different viruses. (Ref.1)
The coronavirus, SARS-CoV-2
SARS-CoV-2 is an RNA virus, meaning it has a single-stranded RNA as its genome. This is a common feature among the coronavirus family. Their genome is considered as one of the largest among the RNA viruses. SARS-CoV-2 has about 13 genes. The genes, orf 1a and orf 1b encode for replicase, the enzyme required for the replication of viral RNA. Other proteins encoded by its genome are structural proteins that are crucial for the development of envelope, membrane, nucleocapsid, and spike of the coronavirus. Accessory proteins are also synthesized; these proteins are surmised to facilitate or modulate the infection process. (Ref.2) Genomic research analyses between SARS-CoV-2 and SARS-CoV revealed a high homology at the nucleotide level. However, six regions of difference (RD) were identified between the two genomes. These RDs could serve as potential markers for identification as well as for creating new drugs. (Ref.3) Proteomic analysis, in turn, showed that SARS-CoV-2 proteins have about 95% to 100% homology to SARS-CoV proteins. Conversely, two SARS-CoV-2 proteins, Orf8 and Orf10, apparently have no homologous proteins in SARS-CoV. (Ref.3)
Both coronaviruses use their S protein to bind to the target cells, e.g. lung cells, to initiate infection. In particular, the S protein binds to the angiotensin-converting enzyme 2 (ACE2) receptor on the host cell surface. Once inside the cell, they begin to replicate in the cytoplasm. SARS-CoV-2, by contrast, is more efficient at using ACE2 receptors than SARS-CoV. (Ref.3) Thus, compared with SARS-CoV, the coronavirus SARS-CoV-2 is likely to have a greater pathogenicity and yet it is less virulent in terms of the extent of tissue injury.
The coronavirus disease, COVID-19
Currently referred to as COVID-19 (coronavirus disease, 2019), the disease was posited to come from Wuhan, China.(Ref.4) The virus was found to be genetically similar to the bat coronaviruses. Thus, scientists presumed it originated from bats. Bat soup is a delicacy in China. Thus, seeing bats being sold live in cages at Chinese poultry and seafood markets in various parts of China, including Wuhan, is not uncommon. Scientists hypothesized that the coronavirus ”jumped” from bats to humans as host. Another potential source is the pangolin. By metagenomic studies, 70% of tested pangolins were found to harbor coronaviruses with a sequence (corresponding to the receptor-binding site of the genome) to be about 99% similar to SARS-CoV-2’s. (Ref.5) Pangolin meat and scales were being sold in China although this practice is banned. Unfortunately, illegal trades and smuggling of the animal persisted, mainly, due to its use in traditional medicine. (Ref.5)
The coronavirus now circulating in humans can be contracted primarily by catching infected small droplets from the sneeze or cough of the carriers. The latency of COVID-19 on average is slightly longer than that of SARS. (Ref.3) While SARS entails a more severe case fatality rate (9.6%), COVID-19 is estimated to be less than 2%. (Ref.6,7)
As a precaution and preventive measure, the World Health Organization (WHO) recommended to regularly wash hands and to stay at a safe distance from people manifesting COVID-19 symptoms, e.g. coughing, fever, and shortness of breath.
Despite the enormous effort of the health sector from around the world, the peril remains vast and immense. A terrifying prediction forewarns that the virus reaching a pandemic status is very much likely. COVID-19 may not be as fatal as SARS but it is more challenging to contain. While there were serious and fatal cases, there were also many instances when SARS-CoV-2 carriers showed no symptoms at all. (Ref.8) With SARS, people harboring the virus almost always showed symptoms, and thus, they could easily be identified and isolated. With COVID-19, there is a heightened risk. Some people could be carrying the virus and then pass it to others unaware because of the covert symptoms. Thus, by the coming year, about 40% to 70% of people worldwide are estimated to be infected with SARS-CoV-2, with some people showing severe illness while others will have milder to no symptoms. (Ref.8)
Because of the foreboding health cataclysm, governments from all over the world are implementing containment measures. In Australia, daily life could be disrupted with the possible closure of schools and offices as the disease is feared to cause havoc. One factor is their aging population. 16% of their population is over 65. (Ref.9) Older people have weaker immune defense. Thus, they are more susceptible, and the more susceptible individuals there are, the greater is the struggle of the healthcare system to cope up. The map below shows that there are now 44 countries with reported cases of COVID-19. As of February 26, the outbreak affected more than 82,000 and at least 2,795 people have died. (Ref.10)
On Tuesday (February 25th), the U.S. Centers for Disease Control and Prevention issued a warning over possible community outbreaks. Nancy Messonnier, the director of the CDC’s National Center for Immunization and Respiratory Diseases, said that Americans should prepare and now is the time. (Ref.11) Further, she said, “We expect we will see community spread in this country. It is not a matter of if, but a question of when, this will exactly happen”. Expect that standard measures will be implemented. There could be extensive travel bans, closure of establishments, and cancellation of public gatherings, such as sporting events, concerts and business meetings. Scarcity due to stockpiling of essential household items and food may also ensue.
COVID-19 has not reached the pandemic status yet but it is expected and deemed inevitable. Each one of us should not be too at ease in dealing with a deadly respiratory virus, such as SARS-CoV-2. Tom Frieden, the former director of the U.S. Centers for Disease Control and Prevention, talked about the eight things that must be done. (Ref.12) First and foremost, we ought to know the enemy. Find out what makes the virus pathogenic and deadly. Are there areas, genetic or structural, that can be targeted in order to impale the virus? Spreading the virus must be stopped. If curtailing school hours or an option to work at home could deter the spread of the virus, then, all these could well be taken so as to mitigate the rapid spread of the virus. We should support both local and international public healthcare systems. Healthcare workers must be provided with the utmost protection, making sure that they are provided with appropriate masks and suits. Local healthcare system should prepare now before a surge of critically-ill patients arriving en masse occurs. Medicines and medical supplies should also be sufficient to prevent disruption in day-to-day health care. The social needs of the patients and their families must be upheld. Aside from medicines, strength is drawn from the support, warmth, and love coming from the people that matter. Lastly, businesses could be disrupted; thus, preparedness is crucial to avoid any further detriment to the economy.
— written by Maria Victoria Gonzaga
- Naming the coronavirus disease (COVID-2019) and the virus that causes it. (2019). Who.Int. https://www.who.int/emergencies/diseases/novel-coronavirus-2019/technical-guidance/naming-the-coronavirus-disease-(covid-2019)-and-the-virus-that-causes-it
- McBride, R., & Fielding, B. (2012). The Role of Severe Acute Respiratory Syndrome (SARS)-Coronavirus Accessory Proteins in Virus Pathogenesis. Viruses, 4(11), 2902–2923. https://doi.org/10.3390/v4112902
- Xu, J., Zhao, S., Teng, T., Abdalla, A. E., Zhu, W., Xie, L., Wang, Y., & Guo, X. (2020). Systematic Comparison of Two Animal-to-Human Transmitted Human Coronaviruses: SARS-CoV-2 and SARS-CoV. Viruses, 12(2), 244. https://doi.org/10.3390/v12020244
- W.H.O. Declares Global Emergency as Wuhan Coronavirus Spreads. (2020, January 30). The New York Times. https://www.nytimes.com/2020/01/30/health/coronavirus-world-health-organization.html
- Cyranoski, D. (2020). Mystery deepens over animal source of coronavirus. Nature. https://doi.org/10.1038/d41586-020-00548-w
- Smith, R. D. (2006). Responding to global infectious disease outbreaks: Lessons from SARS on the role of risk perception, communication and management. Social Science & Medicine, 63(12), 3113–3123. https://doi.org/10.1016/j.socscimed.2006.08.004
- Dorigatti, I., Okell, L., Cori, A., Imai, N., Baguelin, M., Bhatia, S., Boonyasiri, A., Cucunubá, Z., Cuomo-Dannenburg, G., Fitzjohn, R., Fu, H., Gaythorpe, K., Hamlet, A., Hinsley, W., Hong, N., Kwun, M., Laydon, D., Nedjati-Gilani, G., Riley, S., … Ferguson, N. (n.d.). Report 4: Severity of 2019-novel coronavirus (nCoV) WHO Collaborating Centre for Infectious Disease Modelling MRC Centre for Global Infectious Disease Analysis J-IDEA Imperial College London. https://www.imperial.ac.uk/media/imperial-college/medicine/sph/ide/gida-fellowships/Imperial-College-2019-nCoV-severity-10-02-2020.pdf
- Hamblin, J. (2020, February 24). A Vaccine Won’t Stop the New Coronavirus. The Atlantic; The Atlantic. https://www.theatlantic.com/health/archive/2020/02/covid-vaccine/607000/?utm_source=facebook&utm_campaign=the-atlantic-fb-test-1316-3-&utm_content=edit-promo&utm_medium=social&fbclid=IwAR3YmgEaWQbJh8yrFFQcXFJmDp9m4tWO4sUhwf3hVnzzpogm-AiG3h4Nvo0
- Moore, C. (2020, February 26). Why coronavirus may hit Australia worse than in China. Mail Online; Daily Mail. https://www.dailymail.co.uk/news/article-8048957/Why-coronavirus-hit-Australia-worse-China.html?fbclid=IwAR22S7lOtJKfzn_jDfRPBYSXgeKHgW71bLOuW8YTtURkwtWyUW6Csn3aGl0
- Coronavirus Map: Tracking the Spread of the Outbreak. (2020, January 28). The New York Times. https://www.nytimes.com/interactive/2020/world/asia/china-wuhan-coronavirus-maps.html
- Trump’s Upbeat Virus Prediction Undercut by New CDC Warning (1). (2020). @BloombergLaw. https://news.bloomberglaw.com/health-law-and-business/trump-officials-to-defend-coronavirus-plans-before-congress
- Dr. Tom Frieden. (2020, February 25). What do you need to know about coronavirus? CNN. https://edition.cnn.com/2020/02/25/health/coronavirus-pandemic-frieden/index.html