As the world wakes up to this Friday morning, it sadly discovers that the number of SARS-CoV-2 -sometimes simply called coronavirus- infected people has overcome the half million cases, with more than 24000 deaths. Feelings from rage, sorrow, mourning and hopelessness animate these days people lives, driving a natural, perhaps instinctual and poignant need to find a culprit to this world-scale disaster.
News from all over the world rise the possibility of a conspiracy plan, orchestrated by the governments, to create a biological weapon, capable of punishing and/or scaring people. Well, let me tell you why this is NOT the case.
Published just a few days ago, PhD Kristian Andersen and co-authors report evidences that the virus causing COVID-19, SARS-CoV-2, is -to quote- “not derived from any previously used virus backbone” for the following reasons (1):
1) Comparison between the genomic sequences of SARS-CoV-2 and another human infecting coronavirus (SARS-CoV) reveals that the viral sequence responsible for binding the ACE2 receptors on human cells (in short RBD=receptor binding domain) is quite different an it is highly likely to be fruit of a natural selection.
Why is this unlikely to be generated in a lab? The RBD sequence in SARS-CoV-2 shows many similarities to other RBD sequences found in animal coronaviruses suggest that this feature developed via natural evolution.
2) SARS-CoV-2 owns unique sequences -in details a polybasic cleavage site and O-linked glycans- never observed in other animal betacoronaviruses, but existing in other human coronaviruses. These sequences are thought of playing a crucial in the infection process into human cells.
Why is this unlikely to be generated in a lab? While it has been observed that prolonged viral passages in cells and animals can induce the appearance of polybasic cleavage sites (as observed in low-pathogenicity avian influenza virus) (2), yet it is highly unlikely that the O-linked glycans sequence is the result of viral selection in cells or animals. In fact, O-linked glycans are sequences used by our immune system to discriminate between physiological structures or pathogens. The appearance of O-linked glycans sequence in the viral genome could be only justified though direct exposure to human immune system, thing never been described before. Hence, O-linked glycan sequence most likely rose thought natural selection.
Picture credit by Ilaria Vitiello ( on instagram @baba.yaya_)
To recap, in this publication PhD Kristian Andersen and co-authors battle with strong evidenced the idea of a man driven manipulation of coronavirus. The complexity of the changes acquired from SARS-CoV-2 to be able to infect human tissues makes quite unlikely the possibility to be able to create such a virus in a lab.
Remarkably, by scavenging for other proves in literature, it is possible to find many other evidences out-there fighting with scientific arguments the baseless theory of a bioweapons. Here some of the most striking pieces of data pointing towards a real transmission of coronavirus from birds to human:
In 2015, different groups published evidences of the capability for bat infecting coronaviruses to attack human cells (3,4);
In 2018, Peter Daszak and Zhengli Shi showed serological evidences of human infection by bat SARSr-CoVs, in regions close to bat inhabited caves, in Jinning County, Yunnan province, China5. Around 97% of the individuals tested in this screen had been exposed to livestock, pets and wild animals, as the majority of them were farmers (about 85%) (5);
The idea of bats might be “natural reservoirs of SARS-like coronaviruses” were already published in Science by Wendong Li et al in 2005 (6).
Altogether these data indicate how likely the transmission animal-human took place through the years, creating, unfortunately, a new enemy to human health.
In a world affected by a lashing pandemic, science can offer the key to cure and prevent. Rage and vengeance have no place in such a scenario, as it does not bring any solution to what is now threatening global health. Instead, we should highlight how such a harm is revealing that people care for each other, and have an urge to help out, volunteer, offer services, and donate.
Picture author's website:
https://ilariavitiello86.wixsite.com/portfolio
References:
1) Andersen, K.G., Rambaut, A., Lipkin, W.I. et al. The proximal origin of SARS-CoV-2. Nat Med (2020). https://doi.org/10.1038/s41591-020-0820-9
2) Toshihiro Ito, Hideo Goto, Eiji Yamamoto, Hiroko Tanaka, Mutsuko Takeuchi, Masaru Kuwayama, Yoshihiro Kawaoka, Koichi Otsuki, Generation of a Highly Pathogenic Avian Influenza A Virus from an Avirulent Field Isolate by Passaging in Chicken, Journal of Virology May 2001, 75 (9) 4439-4443; DOI: 10.1128/JVI.75.9.4439-4443.2001
3) Menachery, V., Yount, B., Debbink, K. et al. A SARS-like cluster of circulating bat coronaviruses shows potential for human emergence.Nat Med 21, 1508–1513 (2015). https://doi.org/10.1038/nm.3985
4) Vineet D. Menachery, Boyd L. Yount, Amy C. Sims, Kari Debbink, Sudhakar S. Agnihothram, Lisa E. Gralinski, Rachel L. Graham, Trevor Scobey, Jessica A. Plante, Scott R. Royal, Jesica Swanstrom, Timothy P. Sheahan, Raymond J. Pickles, Davide Corti, Scott H. Randell, Antonio Lanzavecchia, Wayne A. Marasco, Ralph S. Baric. SARS-like WIV1-CoV poised for human emergence. Proceedings of the National Academy of Sciences Mar 2016, 113 (11) 3048-3053; DOI:10.1073/pnas.1517719113
5) Wang, N., Li, S., Yang, X. et al. Serological Evidence of Bat SARS-Related Coronavirus Infection in Humans, China. Virol. Sin. 33, 104–107 (2018). https://doi.org/10.1007/s12250-018-0012-7
6) Wendong Li, Zhengli Shi, et al, Bats Are Natural Reservoirs of SARS-Like Coronaviruses
SCIENCE, 28 OCT 2005 : 676-679