What is the Health Line on My Vaccine Immunity?

Tomorrow I am to get my first shot to start the process of becoming immune to the COVID 19 virus. I have worked with students in person since June of 2020, for almost all of the pandemic, so I am so excited to receive my first shot. Since I am getting only the Moderna or the Pfizer shot, I also wondered what would be my immunity after the first shot, and even the second shot? So I turn this blog over to Healthline to give us some clear information. The rest of today’s blog is from their website:

What level of immunity do you have after the first vaccine?

Even though the Pfizer-BioNTech and Moderna vaccines require two doses, you do get some immunity after you receive the first dose. Let’s examine this in a little more detail below.


Researchers working on the clinical trials for the Pfizer-BioNTech vaccine observed a vaccine effectiveness of 52 percent between the time of the first and second doses, which is a 21-day period.

However, the Pfizer-BioNTech vaccine may be more effective after the first dose than was previously thought. This information comes from a separate analysis from scientists in the United Kingdom.

These scientists wanted to look at vaccine effectiveness 15 days or more after people had received the first dose of the Pfizer-BioNTech vaccine. They found that vaccine effectiveness was actually closer to 89 to 91 percent 15 days after the first dose.


In a reportTrusted Source submitted to the FDA, researchers discussed vaccine effectiveness in clinical trial participants who’d only gotten one dose of the vaccine.

A vaccine effectiveness of 50.8 percent was found up to 14 days after the first dose. Vaccine effectiveness was 92.1 percent beyond the first 14 days.

What level of immunity do you have after the second vaccine?

Now let’s look at immunity after receiving the second dose of the Pfizer-BioNTech or Moderna vaccine.



Researchers working on the Pfizer-BioNTech vaccine clinical trial looked at vaccine effectiveness 7 days after the second dose. At this point, vaccine effectiveness was observed to be 95 percent.

And what about longer-term immunity? A separate study, currently in preprint, looked into this. This study followed people for 63 days after they’d received their second dose.

The researchers observed a strong antibody response following the second dose. While the overall levels of antibodies began to decrease slowly as time passed, they still remained high at the 63-day mark.



Investigators working on the Moderna clinical trial evaluated vaccine effectiveness 14 days after trial participants had gotten their second dose.

Vaccine effectiveness was 94.1 percent at this point.

Researchers also published a separate study of the immune response to the Moderna vaccine 90 days after the second dose. This study was rather small, involving 34 participants.

High levels of antibodies were made following the second dose. Similar to the Pfizer-BioNTech study discussed above, antibody levels started to slowly decrease over time. However, immunity persisted at high levels at the 90-day mark.

Dr. Robert A. Southworth, Jr.

Dr. Robert A. Southworth, Jr.

Share this article:

Leave a Reply

Your email address will not be published. Required fields are marked *

More from EdSpeak

Discover the tools and strategies modern schools need to help their students grow.

Community Schools Reform

As a seasoned researcher of K-12 public schools and someone dedicated to improving the quality, equity, and creativity in education, I wholeheartedly support the proposal

Read More »

Subscribe to EdSpeak!

The SchoolWorks Lab Blog, connecting teaching to policy through research.