rMA15: the story of mice adapted SARS-COV-1. Since 2007 SARS was studied on rats in biolabs.


London, 24 April 2020 – In January 2007 in the US Laboratory of Infectious Diseases of National Institute of Allergy and Infectious Diseases, in Bethesda, Maryland, researchers were carrying out experiments on SARS-CoV virus after 2003 epidemic caused by a novel coronavirus (SARS-COV-1) that originated in bats.

They decided to use mice as models of human SARS disease as they are easily accessible and relatively inexpensive. As mice support SARS-coronavirus replication in the respiratory tract, but do not develop the disease, the team decided to ‘potentiate’ SARS-COV-1 by adapting it: as one single inhalation of the virus did not produce effects, they made 15 serial passages in the respiratory tract of young mice. The use of this mouse-adapted virus allowed studies on viral disease and its prevention in a mammalian host

This way a new biologically derived virus, rMA15 was born in a laboratory following 15 intranasal inoculations of SARS-COV, lethal even for the high resistant mice. The virus is not a result of engineering but biological mutation.

“We adapted the SARS-CoV (Urbani strain) by serial passage in the respiratory tract of young BALB/c mice. Fifteen passages resulted in a virus (MA15) that is lethal for mice following intranasal inoculation” the study reports. ”The virulence and lethality of the MA15 virus result from six mutations in the SARS-CoV genome that occurred within 15 passages through BALB/c mice. Introduction of these six mutations into a recombinant SARS-CoV infectious clone, rMA15, conferred a lethal phenotype on the virus for young BALB/c mice”.


That way scientists since 2007 could observe and study effects of SARS-COV induced illness more easily. MA15, much more lethal than the original SARS-CoV, started to be used in laboratories for research of vaccines because experts after 2003 epidemic launched the alarm on high risk of pandemics.

​“The MA15 virus has six coding mutations associated with adaptation and increased virulence; when introduced into a recombinant SARS-CoV, these mutations result in a highly virulent and lethal virus (rMA15), duplicating the phenotype of the biologically derived MA15 virus. Intranasal inoculation with MA15 reproduces many aspects of disease seen in severe human cases of SARS.

Thereafter the adapted rMA15 was used in researches to assess whether SARS-CoV like viruses circulating in bats can infect directly humans, so a new recombinant virus was created in which the gene encoding the spike glycoprotein of SARS virus was swapped with the gene from a bat virus called SHC014 and the SARS-CoV used in the experiment was in fact SARS-MA15.

​The result was a recombinant virus called SHC014-MA15, an engineered one which replicated well in a human epithelial airway cell line and in primary human airway epithelial cell cultures. One of the results of the experiment was that the spike glycoprotein of a bat coronavirus can mediate virus entry into human cells showing a viral genome sequence alone is not enough to establish the infectivity and danger to humans.

The new SHC014-MA15 was labelled by some media as the new SARS 2.0. But some virologists say this alarm wasn’t justified. 

Here is what the Center for Retrovirus Research, The Ohio State University, Columbus, OH, USA said: last Feb 26 2020. “No credible evidence supporting claims of the laboratory engineering of SARS-CoV-2 because this virus is undoubtedly distinct from SL-SHC014-MA15, with >6,000 nucleotide differences across the whole genome. Therefore, once again there is no credible evidence to support the claim that the SARS-CoV-2 is derived from the chimeric SL-SHC014-MA15”.​

The prestigious Nature in 12 November 2015 warned over risky research in November 2015. But an Editors’ note, last March makes clear: “We are aware that this story is being used as the basis for unverified theories that the novel coronavirus causing COVID-19 was engineered. There is no evidence that this is true; scientists believe that an animal is the most likely source of the coronavirus.”

All scientists have drastically ruled out the present pandemic SARS-COV-2 is an engineered virus and any relation with SL-SHC014-MA15 virus as this is engineered.

But rMA15 virus, instead, is not an engineered one; it is the natural, biological outcome of 15 inhalations in mice of SARS-CoV-1 which simply biologically mutated inside the animal. All scientists reckon SARS-CoV-2 comes from an animal.

At present researchers don’t know if SARS-CoV-2 immediately started to spread in humans after a single transmission from an animal, or if it took multiple zoonotic events between an infected animal population and humans.

Why then, if mice infected with rMA15 were so widely used in laboratories across the globe, this have never been mentioned as possible cause of the present pandemic? Because genome is different? How many generations of mice are needed for a virus mutation then? What other experiments and biological passages have been made since 2007 with MA15? Maybe these have not been published? Or the virus rMA15 escaped the lab years ago to mutate outside the lab?

Over these months we have been told that this pandemic originated from a bat or pangolin which infected a human in Wuhan wet market where bats are not even being sold. But any other plausible assumptions on laboratory escape are ruled out as unverified theories, conspiracy theories, irresponsible, sensationalists mediatic attacks to the scientific community.

Meanwhile journalist trying to investigate what happened in Wuhan laboratory at few steps away from the wet Market are detained by police and forcibly quarantined by Chinese government.

Many information emerged over the last two months about biolabs weak and internationally inconsistent regulation, laboratories escapes and the amount of ongoing research on SARS.

In the New York Post of last 22 Feb, journalist Steve W. Moshes explains that after 2003 SARS outbreak, SARS-CoV virus escaped from virology labs more than once in China and that the country’s only Level 4 microbiology lab equipped to handle deadly coronaviruses is right Wuhan National Biosafety Laboratory. He lays out the chance laboratory workers became infected accidentally and then infected families and friends and brings as supporting evidence the fact that Chinese Ministry of Science and Technology issued a new directive: “Instructions on strengthening biosecurity management in microbiology labs that handle advanced viruses like the novel coronavirus”, right in the frame of measures to contain the outbreak. 

At this stage, should we still believe the Wuhan wet market stories of bats and pangolins?

Wouldn’t be more honest to admit that researches are ongoing on the actual incident that caused the pandemic? The way laboratory escapes reports are drastically targeted as baseless attacks to scientific evidence sounds frankly as a collective defence on the side of the scientific community and on the one of the pharma corporates which finance laboratory research: they fear discredit and anger in a moment of exasperation of the public opinion.

Laboratory accidents can happen. Day will come the scientific community will have to admit this has been the case.


A mouse-adapted SARS-coronavirus causes disease and mortality in BALB/c mice. 

No credible evidence supporting claims of the laboratory engineering of SARS-CoV-2 

A SARS-like cluster of circulating bat coronaviruses shows potential for human emergence

SARS-CoV-2 Vaccines: Status Report 

Molecular Determinants of SARS -COV Pathogenesis and Virulence in Young and Aged Mouse Models of Human Disease

Genomic variations of COVID-19 suggest multiple outbreak sources of transmission

Don’t buy China’s story: The coronavirus may have leaked from a lab


                                                                                                                                                                          Copyright © TalkEurope.org 2020