COVID-19 Vaccine: Mike Hori, MD, Infectious Disease Specialist Answers Questions

Mike Hori, MD answers questions about the COVID-19 vaccine. Excerpts from this interview are included below the video.

1. Will you explain how the COVID vaccine research followed a rigorous course of testing and why we should trust it? (0:23) -4 phases of human study, then passed to the FDA for study to decide if vaccine is safe and effective as advertised.

2. Can you tell us more about the different types of people involved in the trials? (5:14) -People were involved from all over the country and many racial ethnic groups. 10% of both Pfizer and Moderna were black, 13-20% latinx, and over a broad age range.

3. The mRNA vaccines are using a new process. What makes them different from prior vaccines? (6:33) -Instead of injecting the actual material, we are giving our bodies “messenger RNA” that instruct our cells to construct protein that our bodies will respond to and destroy, creating immunity.

4. What are the major differences between the Pfizer and Moderna vaccines? (8:39) – They are both mRNA vaccines. Pfizer can be given to people age 16+, and Moderna is 18+. There is more mRNA in Moderna. Pfizer has to be kept colder than Moderna. Moderna is viable longer once thawed, easier to have in normal clinics. Both work the same at 95% efficacy, and the same side effects.

5. Why should we trust that mRNA vaccines are safe and effective, including the COVID-19 vaccine? (10:17) – Rigorously phased program. Some people may develop an allergic reaction, but this is not unusual. Regarding efficacy, testing was easier to complete during a pandemic as having a lot of community spread makes it easy to tell if it’s effective.

6. What are the common side effects and are there potential long-term health risks of getting the vaccine? (12:46) -Arm soreness at the injection site, headache and fatigue are most common. Some people have nausea or diarrhea, and fewer at 3% have mild fever or chills. Most of these issues resolve in 24-48 hours. Not seeing any long-term issues in any meaningful way.

7. Why do you need two doses of the vaccine? Will you have any protection if you miss the second dose? (15:14) -We need to prime and then boost. This is not uncommon, and many vaccinations work this way. Only getting one you may get some immunity, but it won’t be as much, and we strongly suggest both doses.

8. How long does it take after getting both doses for you to start having have an immune response and then how long for maximum effect to occur? (17:10) -With Pfizer you get some immunity after 10 days, but max benefit is ~7 days after the 2nd dose for Pfizer and 14 days for Moderna.

9. Why do we still have to continue wearing PPE here at the hospital, and masks around others in public? How long will we have to do this? (17:57) -We know the vaccine helps protect us from getting sick, but we don’t know if it will keep us from getting infected and still being infectious to others. We probably won’t consider relaxing community precautions until at least halfway through 2021 if not after.

10. Should people who have tested positive for COVID-19 get the vaccination? (20:08) -They can be offered the vaccine and can get it and it’s safe.

11. How should I schedule other vaccines around the COVID vaccination? (21:12) -It is best not to have another vaccination for two weeks before or after.

12. Will the vaccine cause someone to test positive for COVID-19 (in other words, a false positive) (21:58)? -No, this vaccine will NOT give you a false positive test.

13. How does this vaccine compare to other vaccines in causing reactions like Bell’s palsy or anaphylaxis? Also, are their concerns for immune-suppressed patients? (22:19) – This vaccine is the same as any other vaccine in that there is always a risk of allergic reaction. This is not a live vaccine, so it shouldn’t be dangerous even if you have immune suppression, but it’s hard to say.

14. Is it okay to drive after having the vaccination? (24:55) – Yes, you can drive just fine.

15. What can you recommend for pregnant or lactating women about getting the vaccine? (25:35) -Pregnant and lactating women weren’t included in the studies, but it’s not a living vaccine so transmission is not possible. American College of OBGYN and Society of Maternal Fetal Med both recommend the vaccine for pregnant and lactating women.

16. Should we avoid taking any medications before or after our vaccine appointment? (27:37) – There are no over-the-counter meds that we know of that you should not take. For complex prescription meds, talk to your doctor.

17. We have heard about mutations of the virus and in WA State the governor has restricted travel from the UK and some other countries. Should we be concerned about it? (28:38) – The mutating virus in the UK is more transmissible, which is an issue, but the vaccine should work well against the virus.

About The Author

Valley Medical Center's Marketing and Community Outreach Office


  1. Richard Nieman

    I am 82 years old and you say that Jan I can get a shot for Covid, but when and where can i get the shot?

    1. Valley Communications

      Thank you for reaching out for more information. When we are ready to schedule appointments for patients who qualify for Phase 1B, we will update this page: and also notify patients via MyChart. Currently we are vaccinating healthcare workers and first responders only to align with Phase 1A of the vaccine distribution guidelines seen here:…/VaccineAllocationPhase1A.pdf

  2. Sonia Gaston

    Dr. Hori,

    I’m a 67 year old female with MS, my only undying medical .
    My husband will be 70 the end of Feb.
    Rick can get an injection after his 70th, the problem is we leave for Mail for 2 months. Will he be able to get his second injection on Maui?
    Next…I can’t see that I fall into any phase category.
    66… one medical condition, just the two of us in our home. Can you please tell me when I will be able to get the Covid Vaccine? Thank you.

    1. Valley Communications

      We cannot guarantee that your husband will be able to get his second dose in Maui, that depends on supply and accessibility in Hawaii. If you’re not leaving for another month, please schedule an appointment as soon as you are able so you can get both doses before you go.

    1. Valley Communications

      We have Pfizer and Moderna both available, but we are unable to reserve a specific type for staff or patients. We must deliver whatever type we currently have in supply which is delivered to us by the state. We encourage you to research both so you are aware of any side effects to expect. Please visit our vaccination web page for more information.

  3. Michael Mattson

    I’ve signed up to get shot but the system did not work fir my wife I noted I wanted her to get shot too on my sign up sheet. Will she be able to get her shot too?

    1. Valley Communications

      We are so glad you were able to schedule an appointment to get your vaccine. Unfortunately, if your wife does not have a confirmed appointment, we will not be able to accommodate a shot for her during your appointment. If your wife qualifies for vaccination, please monitor MyChart or call 425.690.3630 to schedule. For more information on eligibility please visit our vaccination web page.

Comments are closed.