Updated on Jun 30, 2022 | COVID-19, Featured, Your Health
The novel coronavirus is transmitted through the air and replicates in the respiratory system and in blood.
The novel coronavirus that began in Wuhan, China, has been labeled a Public Health Emergency by the U.S. government. As confirmed cases of the coronavirus now known as COVID-19 continue to increase in this country and around the world, and additional information unfolds, two renowned microbiologists at the Icahn School of Medicine at Mount Sinai, Peter Palese, PhD, and Adolfo García-Sastre, PhD, recently provided insights into the disease. Dr. Palese is the Horace W. Goldsmith Professor and Chair of the Department of Microbiology, and Professor of Medicine (Infectious Diseases); and Dr. García-Sastre is the Irene and Dr. Arthur M. Fishberg Professor of Medicine (Microbiology, and Infectious Diseases), and Director of the Global Health and Emerging Pathogens Institute.
What is COVID-19?
Dr. Palese: It belongs to a group of viruses known as coronaviruses, to which the SARS (severe acute respiratory syndrome) virus and MERS virus (Middle East respiratory syndrome) belong. It is transmitted through the air and replicates in the respiratory system and in blood.
Dr. García-Sastre: The COVID-19 and the SARS-CoV are closely related and they originated from bats. In the case of the COVID-19, we are not yet sure of its precise origin—whether the virus went directly from bats to humans or whether it went from bats to a host animal and then to humans, which is what happened with SARS. But we believe it originated from bats.
The SARs outbreak in 2003 is different from the novel coronavirus in that it was traced to civet cats and raccoon dogs, which were eaten as a delicacy in some parts of China. The animals were originally infected by bats—either through bites or by breathing in bat urine and feces. MERS, a respiratory illness relatively new to humans and traced to the Arabian Peninsula, is believed to have been spread by camels that were also infected by bats.
How did this novel coronavirus start?
Dr. Palese: Samples of the virus were found in a large fish market in Wuhan where other live animals are kept in cages and sold as food.
Dr. García-Sastre: People went to the market to buy food and were exposed to the virus, which infects through the respiratory tract. Like the flu, it is spread by aerosols.
What are the most important factors to consider as the disease unfolds?
Dr. Palese: The reproduction number, or “R” number, appears to be around 2.5. That means every person who is infected will pass the disease on to 2.5 other people. The influenza virus is a little lower. Measles has a much higher R number of about 18. These are averages. But we have to be vigilant. There are reports that the disease can be transmitted for about 24 hours before symptoms develop. If that is confirmed, it would make it more difficult to contain. The disease caused by the novel coronavirus is accompanied by flu-like symptoms, including very high fever. Fatalities stem from pneumonia and comorbidities, such as old age, asthma, or chronic obstructive pulmonary disease.
Dr. García-Sastre: Don’t panic. The virus does not seem to be associated with very high mortality. It is progressing more quickly than the SARs virus did, but it also appears to be less deadly. The rate of transmission appears to be similar to that of the seasonal flu. That is an estimate because we don’t know for sure whether all of the people who have the disease have been diagnosed. Some may have very mild cases. Another consideration is at what moment does an infected person begin to transmit the virus? With flu, people can transmit the disease before there are symptoms. With SARS, most transmissions happen after there are symptoms.
Are vaccines available?
Dr. Palese: Our government is rapidly developing vaccines and they are in the pipeline, but nothing has been approved as of today.
Dr. García-Sastre: Vaccines may be first available only on an experimental basis.
Updated on Jun 30, 2022 | Featured, Infectious Diseases, Research
Mount Sinai scientists, from left, Peter Palese, PhD; Florian Krammer, PhD, with a 3D model of the influenza virus hemagglutinin; and Adolfo García-Sastre, PhD.
The quest to develop a universal influenza vaccine that would be administered only once or twice in an individual’s lifetime and cover every strain of the virus moved closer to becoming a reality in October, when researchers at the Icahn School of Medicine at Mount Sinai showed that a novel method of protection against the influenza virus was safe and induced strong immune responses in humans.
The interim results of this phase 1 clinical trial—led by Mount Sinai scientists Florian Krammer, PhD; Peter Palese, PhD; and Adolfo García-Sastre, PhD—were published online in the October 17, 2019, issue of The Lancet Infectious Diseases.
Two types of proteins, hemagglutinin and neuraminidase, cover the surface of the influenza virus. Current influenza vaccines target the head of the hemagglutinin—a structure that changes often. Mount Sinai’s strategy, known as chimeric hemagglutinin (cHA), targets the stalk of the hemagglutinin, which is less variable.
In the Lancet Infectious Diseases study, the research team tested several cHA vaccine regimens in combination with an adjuvant, an ingredient that boosts the immune response to vaccines. All of the regimens induced antibody responses. But, “one vaccine regimen induced a broad antibody response after the first dose, and this response was not only cross-reactive for the currently circulating influenza virus but also to avian (bird) and bat influenza subtypes,” according to Dr. Krammer, Mount Sinai Professor of Vaccinology and Professor of Microbiology at the Icahn School of Medicine at Mount Sinai.
This, he says, showed that one vaccination might be enough to induce protection against changing seasonal influenza viruses and pandemic influenza viruses yet to arise. “The results indicate that we are moving toward a universal influenza vaccine, but these are still interim results.”
Dr. Palese, Horace W. Goldsmith Professor of Medicine, and Professor and Chair of the Department of Microbiology at the Icahn School of Medicine at Mount Sinai, says the “ideal vaccine, given only once in a lifetime and protective against all influenza virus strains,” would go a long way in improving the health of millions of people in the United States and around the world.
A universal vaccine would overcome “antigenic drift,” the small changes in the genes of influenza viruses that render viruses different from one another and allow them to escape human immunity. This is the primary reason why influenza vaccines vary in effectiveness from one season to another and must be updated every year.
Still, influenza vaccines do offer protection from severe disease and physicians strongly recommend that patients get them annually. Despite their widespread availability, however, more than half of Americans were unvaccinated as of the beginning of December 2019, according to NORC at the University of Chicago, which conducts the National Immunization Survey for the U.S. Centers for Disease Control and Prevention (CDC).
Influenza remains deadly for some. The World Health Organization estimates that influenza-related respiratory illnesses account for between 290,000 and 650,000 deaths per year. Dr. Krammer says, “Developing new vaccines takes a lot of time and it’s hard to estimate how long it will take, but I firmly believe we will have a universal flu vaccine in our lifetime and probably sooner.”
In addition to Dr. García-Sastre, a co-senior researcher on the Lancet Infectious Diseases study, and the Irene and Dr. Arthur M. Fishberg Professor of Medicine, and Director of the Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, contributors included Cincinnati Children’s Hospital Medical Center; Duke University School of Medicine; the University of Chicago; and the nonprofit international health organization PATH. Funding was provided by a grant from the Bill & Melinda Gates Foundation.
