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Understanding the science behind the COVID-19 delta variant and vaccines
General Wellness

Understanding the science behind the COVID-19 delta variant and vaccines

By Shirin Mazumder, MD, Infectious Disease Expert
Posted: August 23, 2021

The science of COVID-19 is constantly evolving, both as more is learned about the virus, the delta variant and how it can be treated. Now going through this fourth surge of the pandemic, there are a few new questions about the virus and vaccines. Dr. Shirin Mazumder, an infectious disease expert at Methodist Le Bonheur Healthcare, answers a few of these common questions.


1. Why is the delta variant more contagious?


The delta variant is nearly twice as contagious as previous variants of COVID-19. It also can cause more severe complications, especially among those who aren’t vaccinated. Recent research revealed that people infected with the delta variant have about 1,000 times the number of viral particles in their nasal swab. This means the viral load is 1,000 times more than other strains. It also becomes infectious more quickly, meaning those who contract the variant are spreading the virus sooner during the course of their infection. It replicates faster, and some ongoing studies suggest that vaccinated people carry the same viral load as those who aren’t.


2. If someone is immunosuppressed, should they still get the vaccine if they are taking other medications that could potentially make the vaccine less effective?


Immunocompromised individuals are at a higher risk of severe disease if they contract COVID-19, so it is very important that they are vaccinated. Vaccination works by teaching your immune system to recognize and fight the virus that causes COVID-19. The COVID-19 vaccination works the same way as any other vaccine by triggering your body’s immune system to generate antibodies that fight the virus. The COVID-19 vaccine mimics parts of the virus that signal the generation of these antibodies that can fight the real virus and give you protection from infection and severe illness.


3. Why do vaccinated people need to continue wearing masks?


We’re learning more about COVID-19 every day, including recent research that shows vaccinated people can transmit the virus. Because there are many among us, including children, who haven’t received a vaccination, The Centers for Disease Control and other organizations recommend wearing a mask to help limit the spread of the disease.


4. Why should I get the vaccine if there are medical professionals who aren’t?


At Methodist Le Bonheur Healthcare, we believe receiving the COVID-19 vaccine is a way to prevent serious illness and death. MLH, as is the case with other healthcare organizations, is committed to protecting the health and lives of healthcare staff, patients, families and the community. Patient- and family-centered healthcare is only possible if healthcare staff can engage safely with those they encounter each day.


5. How did we get a vaccine so fast?


While SARS-CoV-2 hasn’t been seen before, its structure resembles other coronaviruses including SARS and MERS. Earlier research on those outbreaks revealed the spike protein was a good target for the vaccine. The spike protein is the part that binds to a cell and infects it. Scientific collaboration, including free sharing of the genetic sequence of SARS-CoV-2, enabled researchers to quickly establish vaccine platforms to fight the virus. The technology behind the vaccines has been in progress for decades. No steps were skipped in the vaccine development process.


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    6. Do the COVID-19 vaccines shed or release any of their components?

    No. Vaccine shedding is the term used to describe the release or discharge of any of the vaccine components in or outside of the body. Vaccine shedding can only occur when a vaccine contains a weakened version of the virus. None of the vaccines authorized for use in the U.S. contain a live virus. mRNA and viral vector vaccines are the two types of currently authorized COVID-19 vaccines available.


    7. Can the vaccine give me COVID-19?

    No. None of the authorized COVID-19 vaccines contain any live virus and do not cause COVID-19 illness. The Moderna and Pfizer vaccines are what are known as mRNA (messenger RNA) vaccines. mRNA vaccines are a newer class of vaccines where an RNA molecule, packed inside lipid droplets, can mimic the cellular or viral membranes and begin making the spike protein. The immune system recognizes the spike as an invader and mounts a protective response. mRNA vaccines do not contain any actual or live virus. The Johnson & Johnson vaccine is a viral vector vaccine. It uses a different virus, replaces part of its genome with part of the coronavirus genome that contains the spike protein. The vaccine is not an active virus because it doesn’t have its complete genome, but the immune system recognizes it and mounts a protective reaction.


    8. Can the vaccine alter my DNA?

    No. Neither the mRNA nor viral vector vaccines interact or alter your DNA in any way.


    9. If I had COVID-19, do I need the vaccine?

    Yes. Due to the severe health risks associated with COVID-19 and the fact that re-infection with COVID-19 is possible, people are advised to get a COVID-19 vaccine even if they have already had COVID-19. In addition, research showed that vaccinations caused a more robust and durable immune response.


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