The claim: MERS is the same as COVID-19
Most pandemics in the 20th and 21st centuries have been caused by either influenza – such as the 1918 Spanish flu or the 2009 swine outbreak – or a coronavirus.
SARS, or severe acute respiratory syndrome, first appeared in southern China in 2002, and MERS, or Middle East respiratory syndrome, turned up in Saudi Arabia in September 2012.
A year and a half after "coronavirus" entered the common lexicon, many remain confused about the difference between COVID-19 (a particular type of coronavirus) and the broader family of viruses – confusion that has spawned an array of misinformation.
An image accompanying a June 17 Instagram post refers to an episode of the hit television show "Grey's Anatomy" where one of the characters, April Kepner, develops a mysterious rash along her back following a trip abroad. The graphic says another character (Jackson Avery, played by actor Jesse Williams), suggests a possible diagnosis.
"Jackson asks if she has MERS – Middle East respiratory syndrome aka coronavirus," the post says. "It's really odd because season 12 was in 2015."
Actually, there's nothing odd about this: MERS and COVID-19, while related, are not the same virus.
USA TODAY was unable to reach the poster for comment.
MERS and COVID-19 are from the same coronavirus family
You probably never heard about coronaviruses before January 2020, when the World Health Organization declared a new coronavirus was likely responsible for a spate of pneumonia-like cases in Wuhan, China.
But this family of viruses has been circulating among humans and animals such as birds, bats, and pigs for centuries, and some dating techniques place its origins almost 11,000 years ago.
Taking their name from the distinctive spike proteins lining the viral surface that resemble a crown, human coronaviruses weren't discovered until the mid-1960s. This group of seven consists of four viruses considered less severe and three highly pathogenic ones: Severe Acute Respiratory Syndrome (or SARS), Middle East Respiratory Syndrome (or MERS) and COVID-19.
All human coronaviruses are believed to originate with bats, though scientists say the disease typically is passed to mice and other domesticated animals before jumping to people.
The two are genetically distinct from one another
Just because two viruses are members of the same family doesn't mean MERS and COVID-19 are identical.
According to genetic analyses of SARS, MERS and COVID-19, the novel coronavirus is considered about 80% genetically similar to SARS and only 50% similar to MERS.
These genetic dissimilarities translate to many differences, an important one being the viruses' spike protein.
Spike proteins are structures coronaviruses use to essentially enter and infect a potential host cell, much like a burglar breaking into a building. The "locks" picked are proteins called receptors that dot the outside of the host cell. They "unlock" when interacting with the spike protein.
But coronaviruses don't all pick the same lock. COVID-19's spike protein prefers angiotensin-converting enzyme 2, or ACE2, a protein found on the surface of many cell types. MERS targets a cellular receptor called dipeptidyl peptidase 4, or DPP4 for short. DPP4 is also found on the surface of many cells, particularly those lining our airways as well as the liver, prostate, and bone marrow.
COVID-19 and MERS also differ in how transmissible and fatal they are.
Unlike the 2002 SARS outbreak, which resolved within 18 months with no further cases to date, MERS continues to cause sporadic infections in humans. This is because the virus remains endemic in camels – its major animal host – who transmit it to humans via unprotected contact. Human-to-human transmission is not easy as it is with COVID-19 unless there's very close, constant contact with an infected person or in a health care setting, according to the WHO.
Infection with MERS is reported to result in more severe disease, a higher chance of hospitalization and a higher mortality rate than COVID-19. But MERS has not spread as far as COVID-19 and has only caused around 2,600 cases and over 860 known deaths worldwide in the last nine years, none in the U.S.
Our rating: False
Based on our research, we rate FALSE the claim MERS is the same as COVID-19. MERS and COVID-19 are from the same family of coronaviruses that have infected humans and animals for centuries. Though they share some genetic similarities, theviruses differ in what kind of host cell proteins their spike proteins target and their degree of transmissibility and fatality.
Our fact-check sources:
U.S. Centers for Disease Control and Prevention, Aug. 10, 2018, Past Pandemics
World Health Organization, Jan. 9, 2020, WHO Statement regarding cluster of pneumonia cases in Wuhan, China
Journal of Virology, April 8, 2013, A Case for the Ancient Origin of Coronaviruses
The Scientist, June 2, 2020, A Brief History of Human Coronaviruses
U.S. Centers for Disease Control and Prevention, July 14, 2017, Zoonotic Diseases
Minnesota Department of Health, accessed June 25, Zoonotic Diseases: Diseases Transmitted from Animals to Humans
International Journal of Biological Sciences, March 3, 2020, Zoonotic origins of human coronaviruses
The Conversation, May 14, 2020, What is the ACE2 receptor, how is it connected to coronavirus and why might it be key to treating COVID-19? The experts explain
Cell Research, July 9, 2013, Structure of MERS-CoV spike receptor-binding domain complexed with human receptor DPP4
U.S. Centers for Disease Control and Prevention, April 26, 2013, CDC SARS Response Timeline
The World Health Organization, March 11, 2019, Middle East respiratory syndrome coronavirus (MERS-CoV)
World Health Organization, accessed June 25, MERS Situation Update
World Health Organization, accessed June 28, WHO Coronavirus (COVID-19) Dashboard
U.S. Centers for Disease Control and Prevention, accessed June 28, COVID-19 Data Tracker
U.S. Centers for Disease Control and Prevention, Aug. 2, 2019, Middle East Respiratory Syndrome (MERS)
The Royal College of Pathologists via YouTube, April 20, 2020, The COVID-19 pandemic: SARS-CoV-2, the virus, and other coronaviruses
Thank you for supporting our journalism. You can subscribe to our print edition, ad-free app or electronic newspaper replica here.
Our fact-check work is supported in part by a grant from Facebook.
This article originally appeared on USA TODAY: Fact check: MERS and COVID-19 are related but not the same