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YSPH Responds

2019-nCoV Coronavirus
Photo by Fusion Medical Animation on Unsplash

Experts from the Yale School of Public Health have been featured at the forefront of the world response to the COVID-19 coronavirus pandemic. We hope these pages reflect the depth and impact that our faculty, staff and students have made in responding to this crisis.

Yale researchers find first cases of new UK coronavirus variant in Connecticut

Gov. Ned Lamont on Jan. 7 announced that Yale researchers in collaboration with the Connecticut Department of Public Health (DPH) detected the first two cases of the SARS-CoV-2 variant B.1.1.7 in the state. This is the same variant initially discovered in the United Kingdom that is associated with increased transmission.

Source: Yale News
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  • Understand COVID-19: Novel Coronavirus Mutations and Variants

    Since the beginning of the COVID-19 pandemic, scientists knew it was a matter of time before new variants of the novel coronavirus, SARS-Cov-2, began to emerge in our communities. For a virus that mutates relatively slowly – picking up an average of two to three new mutations a month – how quickly these distinct variants took root would depend on how well we stopped the spread of the virus. Viruses rely on our cellular equipment to reproduce; mutations can only continue if it keeps infecting people. This particular virus gains access to our cells using its “corona” – a layer of protein spikes that fit into our cellular receptors like a lock and key. But, says Akiko Iwasaki, PhD, “When viruses enter the host cells and replicate and make copies of their genomes, they inevitably introduce some errors into the code.” SARS-Cov-2 is an RNA virus. Unlike many other RNA viruses, though, the novel coronavirus has some ability to check for transcription errors as it replicates. Iwasaki, who studies the mechanisms of immune defense against viruses, compares these errors to a faulty spell-checker. Some of these random errors that get passed on are either neutral or detrimental to the virus. But some errors are beneficial to the virus – making it more contagious, for example – and allow it to proliferate and spread to more people. Over time, the cumulative effects of these mutations may be enough to change how the virus behaves. These “better fit” versions of the virus become the “building blocks of selection,” says Nathan Grubaugh, PhD. These constellations of viral mutations – known as variants – may take hold if there is evolutionary pressure for them to do so. But the novel coronavirus is highly contagious and has spread almost unchecked throughout the world for the last year. It remains a bit of a mystery as to why these variants are emerging now – and what it will mean long-term for vaccination programs. Currently, scientists are optimistic that the three main vaccines available in the US – Pfizer, Moderna and Johnson & Johnson – will continue to provide good immunity. “There are certain mutations in some of these variants that seem to decrease the effectiveness of really important antibodies,” says Grubaugh. “But luckily with vaccines, you don’t just create one antibody, or two or three, you create many different antibodies that recognize all different parts of the virus.” “The mRNA technology is very flexible and can accommodate new mutations,” says Iwasaki. And even if the effectiveness of vaccines dropped to, say, 75 or 85 percent, that would still provide important protection and prevent severe cases of the disease that bring people to the emergency room. Questions about the vaccine remain, however, like whether a fully-vaccinated person could still transmit the virus to another person without being sick themselves. That’s why Iwasaki says it’s still important to continue wearing masks, avoid crowds, and practice good hygiene. “We have all the tools needed to stop the transmission and the spread of these new variants,” Grubaugh emphasized. “If we all put a lot of effort into doing our part, these variants won’t be able to take a foothold in our community at all.

  • Understanding COVID-19: Vaccine Distribution Challenges

    A year into the COVID-19 pandemic, the approval of not only one but several effective vaccines has given us reason to be hopeful. But we now face a new set of logistical and ethical challenges in our unprecedented effort to inoculate the global population. “This is the largest mass vaccination campaign and the most rapid one in human history,” says Andrew Heinrich, a lecturer at the Yale School of Public Health. “And that creates supply chain challenges and distribution challenges.” The first hurdle standing between these life-saving vaccines and the general public are a myriad of supply chain complexities – from manufacturing to transportation to storage. Although significant, these supply chain issues are all surmountable, says viral epidemiologist and Director of the Yale Institute for Global Health, Dr. Saad B. Omer. The larger concern is that these supply chain constraints make it impossible for us to vaccinate everyone at once. Which means we must make strategic and equitable decisions about who to vaccinate first. “We are in a position where it’s necessary to decide who to vaccinate first and all of humanity is benefited when those at greatest risk get vaccinated first,” says Heinrich. Watch this video to learn more about overcoming distribution challenges and how equity plays a crucial role in determining the success of the COVID-19 vaccine rollout.

  • Understanding COVID-19: How mRNA Vaccines Work

    Messenger RNAs, mRNAS, are the messages that the cell uses to create a variety of proteins, which are building blocks and tools for cell function and survival. mRNA vaccines send that message with a blueprint, and it's a message that has an auto destruct feature, like Mission Impossible or a Snapchat message. The mRNA vaccine takes the blueprint of the viral spike protein, and enables the immune system to generate very protective high level neutralizing antibodies. The body recognizes that spike protein and remembers that it has seen it before, so that next time when there is an infection, it attacks the full virus.

    Reports from the phase three trial of these vaccines show remarkable efficacy, even in different ethnic groups and age groups, which is quite significant because older adults tend to have lower responses to vaccines. The vaccines also have an efficacy of 95% of preventing symptomatic COVID disease. And this is very encouraging because this will allow rapid and thorough control of viral infection in the population.

    The study also found that after a single dose of vaccine, some individuals did not approach the target antibody range. The boost from the second dose was needed to provide maximum protection. Additionally, having that booster dose will impact the durability or the longevity of the immune response generated.

    In the past 10 to 15 years in the field of vaccinology and public health preparedness, there's been this focus on technologies in which we as a country and the world invested, without knowing what they would be targeting. mRNA vaccines have been tested in multiple clinical trials before, for infections like the Zika virus, HIV, and influenza. The mRNA vaccines are taking a small piece of the viral sequence and making mRNA out of them. It's not the entire virus, as it's impossible to make a whole virus out of the mRNA. The attractiveness of this technology is that you can program that message into an mRNA relatively quickly and with the vaccines being sorely needed it can be scaled up to meet that demand.

  • What is Herd Immunity?

    In this short video, Yale’s Dr. Howard Forman, physician and professor, discusses herd immunity — what it is and how to achieve it for maximum benefit in the age of COVID-19.

    Credits: OPAC
  • Understanding COVID-19: How Vaccines Work with Your Immune System

    When a virus enters our bodies, our immune system acts to eliminate it. Vaccines mimic the infection, providing a blueprint that tells the immune system how to respond. Immunologists Akiko Iwasaki, PhD, and Ruslan Medzhitov, PhD, explain how the COVID-19 vaccine works to prevent coronavirus from entering our cells.

  • Yale Researchers Identify Saliva as an Accurate Test for COVID-19

    Rapid and accurate testing for Sars-CoV-2 is essential for controlling the ongoing pandemic of COVID-19. The current gold standard is a nasopharyngeal swab but researchers led Anne Wylie, PhD, at the Yale School of Public Health, in collaboration with Shelli Farhadian, MD, PhD, at Yale School of Medicine have identified saliva as a more reliable and accurate means of diagnostic testing. The potential impact of this sampling method could allow many more Americans to be tested for the coronavirus. Click here to read a related article.