#160 – Paul Offit, M.D.: The latest on COVID-19 vaccines and their safety, herd immunity, and viral variants

Paul Offit is a pediatrician specializing in infectious diseases and an expert in virology and vaccine development. He currently serves on the FDA committee evaluating COVID-19 vaccines. In this episode, Paul’s second appearance on The Drive, he provides an update on all the SARS-CoV-2 vaccines currently deployed, explains why the concerns raised around the mRNA vaccines are not legitimate, and offers his view on the prospects and timeframe of reaching herd immunity. He also takes a deep dive into immunology, explaining the short-term and long-term immune response to both natural infection and vaccination and how these two can function together to provide durable immunity. Additionally, they discuss the theories on the origins of this virus, what impact the new COVID-19 variants might have, and the recent pausing of the J&J vaccine. Finally, they discuss how we can be better prepared for an inevitable future outbreak of a novel virus. This episode was originally recorded on April 14, 2021.

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We discuss:

• Overview and current status of the SARS-CoV-2 vaccine strategies [4:10];
• Addressing concerns about mRNA vaccines [9:00];
• How the failure to make an effective HIV vaccine aided the development of a COVID-19 vaccine [16:45];
• Where SARS-CoV-2 falls on the spectrum of its ability to mutate and what that means for immunity and vaccination [21:30];
• How the combination of short-term and long-term immune response to SARS-CoV-2 work together to provide durable immunity [28:00];
• Importance of understanding relative vs. absolute risk reduction [38:15];
• Implications of pausing the J&J vaccine due to reports of blood clotting in the brain [42:45];
• What constitutes herd immunity and the concerns of rising vaccine hesitancy [47:45];
• When we might reach herd immunity, future vaccines for children, and long-term outlook for maintaining population immunity [58:45];
• Theories about the origins of SARS-CoV-2 [1:07:00];
• Preparing for the possibility of a future pandemic and how we can learn from our mistakes [1:10:40]; and
• More.

Overview and current status of the SARS-CoV-2 vaccine strategies [4:10]

This interview includes a discussion of several different kinds of vaccines. Here is an overview of the various types of vaccines:

Figure 1. Overview of vaccine types. Image credit: McGill University COVID19 Vaccine Tracker

• Tens of millions of people have now been vaccinated against SARS-CoV-2

Specific types of SARS-CoV-2 vaccines

• Messenger RNA (mRNA) vaccine 
• Adenovirus vaccine
• Purified protein vaccine
• Live attenuated virus vaccine

Figure 2. Types of COVID-19 vaccines. Image credit: Wellcome

• 1) mRNA is the farthest along in the US
  • FDA granted EUA to Pfizer on Dec 10 and Moderna on Dec 17
  • 120 million have received at least one dose of one of these
• 2) Adenovirus
  • Uses adenovirus as a vector to deliver viral DNA
  • Jenner Institute/Astra Zeneca (AZ): replication-defective adenovirus vector
    • Tens of millions of AZ in UK and Europe
  • Janssen / Johnson & Johnson (J&J): replication-defective adenovirus type 26
    • 200K in west Africa for Ebola
    • more than 6 million in US for SARS-CoV-2 
  • 20 million + doses of these vaccines
  • Russian vaccine is also a replication-defective adenovirus vaccine (human Ad26 followed by human Ad5)
• 3) Purified protein
  • Made by Novavax
  • insert gene for spike protein into baculovirus
  • grown in Spodoptera frugiperda cells (same way we make Flublok)
  • Novavax has been slow to get approval
• 4) Live attenuated
  • still in the works
  • Paul doesn’t think one has been approved anywhere
• 5) Whole killed viral vaccine
  • Used in China on 10+ million people
  • Similar to how we make vaccines for polio, rabies, Hep A, etc. 
  • some question how well it works against SARS-CoV-2
  • Whole killed virus was first used in late 1800s by Louis Pasteur against rabies
• The first vaccines were live non-human viruses
  • Used cowpox in late 1700s
  • The virus was close enough to human smallpox that produced immune response
  • but they didn’t understand the science behind it back then

Addressing concerns about mRNA vaccines [9:00]

• People say mRNA is experimental and like science fiction
  • Peter has tried to point out it’s not as experimental as people think and has been around for decades
    • See Peter’s newsletter: mRNA vaccine technology
  • Now is just the first time we did the final step of sequencing and putting it into clinical practice

{end of show notes preview}

Paul Offit, M.D.

Dr. Paul Offit is a pediatrician specializing in infectious diseases and an expert on vaccines, immunology, and virology. He is the co-inventor of a rotavirus vaccine that has been credited with saving hundreds of lives every day. Offit is the Maurice R. Hilleman professor of vaccinology, professor of pediatrics at the Perelman School of Medicine at the University of Pennsylvania and director of The Vaccine Education Center at  Children’s Hospital of Philadelphia (CHOP). Dr. Offit is currently a member of the National Institutes of Health (NIH) working group on vaccines, a subgroup of the Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV) project that is planning a strategy to combat COVID-19. He is also a member of the FDA’s Vaccines and Related Biological Products Advisory Committee (VRBPAC). Previously, he was a member of the Centers for Disease Control and Prevention’s (CDC) Advisory Committee on Immunization Practices. Dr. Offit is a board member of Vaccinate Your Family and Autism Science Foundation and the author of eleven books.

Website: paul-offit.com

Twitter: @DrPaulOffit

Facebook: Paul Offit