Will I get a hormone imbalance after a COVID vaccine?

Hormone imbalance after a COVID vaccine - vaccine

We’ve been getting the question: can I get a hormone imbalance after a COVID vaccine? While the COVID vaccine is new to all of us, here’s what insight into past vaccines and reactions can tell us about hormones and vaccines.

Your immune response and how COVID vaccines help you build immunity

Hormone imbalance after a COVID vaccine- how your immune system responds to a vaccine- drawing dose from vial

When you’re vaccinated, a number of changes happen within the body. We may think of our immune system as one thing, but there are two main components (with many subsets) that play specific roles and work together to help your body respond to a threat.

One of these is your innate immune system. Your innate immune system works all the time. It’s a first responder in mounting a response to germs. Your skin and its pH, mucus, body temperature regulation, fever, local inflammatory responses (like you likely get around your vaccine site), and more are all ways your innate immune system protects you. When a virus enters your body, it binds to an innate immune system cell. This triggers an immune response. (Which is helpful and happens pretty fast.) But your innate immune system’s job isn’t to target or remember specific pathogens, like COVID-19.

That’s where help from your adaptive immune system comes in. Your innate immune system signals your adaptive immune system for help with specific germs. The adaptive immune system includes B-cells and T-cells. It has capability to remember and store info on different types and strains of germs. While your innate immune system reacts fast, your adaptive immune system takes a little longer to help you build immunity to specific pathogens. But, once it stores that information, it’s quick to remember and respond when the threat arises.

You can see your innate immune system response right around your vaccine site. For example, you might feel redness or warmth. But it’s your adaptive immune system that will help you develop antibodies and build immunity after your COVID vaccine.

I heard COVID vaccines are a newer type of vaccine. How is it different?

coronavirus vaccine vial

The COVID vaccines developed by Pfizer and Moderna are different than the more traditional vaccines we’re used to. Traditional vaccines usually contain a weakened or killed version of a virus, which helps our bodies build immunity.

However, Pfizer’s and Moderna’s COVID vaccines use mRNA technology. That means they do not have any virus particles and work via a different mechanism. Essentially, an mRNA COVID vaccine gives your body instructions to create part of the spike protein seen with the coronavirus. The spike protein sits on the surface of your cells, alerting your adaptive immune system to develop antibodies.

How hormones influence your immune system, your immune response, and what you feel during a vaccine

Hormone imbalance after a COVID vaccine, hormones and immune system- woman wearing a mask and smiling

There’s no direct research linking to a hormone imbalance after a COVID vaccine (or any other vaccination). But your hormones and overall health do play a role in your immune response to a vaccine. And, they could possibly change how you interpret pain from the shot and site reaction.

You could have more injection site pain during your menstrual cycle

Get this: getting a shot while on your period may hurt more. A study by Oxford University shows women’s brains process pain differently while on their periods. This is especially true if you get painful periods. Stimuli can feel worse than it would at other times of month.

So, should you wait to finish your period for your COVID vaccine? That’s between you and your provider. Each healthcare decision is based on your personal medical history and beliefs, plus the benefits versus risks of what’s right for you and your body.

Estrogen may be why women tend to have better immune responses than men to vaccines

The downside is an increased risk of autoimmunity. But, as a whole, women tend to have a stronger immune response than men and we’re better able to produce antibodies to infections. Studies show sex hormones testosterone and estrogen are key. They play a large role in our immune system function. Testosterone slightly suppresses the immune system in some ways. Estrogen enhances it and influences your innate and adaptive immune responses. It has the capability to affect every cell subset in your entire immune system. Estrogen may be one reason why females show a higher vaccine response and antibodies than males, even up to years after a vaccination.

In general, adult females develop higher magnitude immune responses, with respect to antibody levels, and experience more severe adverse events following immunization, due to enhanced immune activation, compared to their male counterparts.

Seminars in Immunopathology, PMID 30547182

So far, there’s no scientific evidence of the opposite: of vaccines affecting estrogen and testosterone. In other words, no hormonal imbalance has been noted after a COVID vaccine (or any other).

How menopause and aging affect vaccine response

Aging is associated with a decline in immune response. Part of this is a loss in estrogen in menopause and postmenopause and its protective benefits on immune function. But as we age, many components of the immune system don’t function as optimally as when we’re younger–for men or women. For example, the body generally produces fewer B-cells and T-cells, the two types of cells mentioned earlier that are important for remembering specific germs.

Cortisol hormone imbalance after a COVID vaccine and your vaccine response

Cortisol is a corticosteroid that is essential to life. It gets called our stress hormone because it’s tied to our stress and helps our bodies respond to threats. It also plays an important part in inflammation and immune system modulation.

But long-term stress and elevated cortisol impacts our overall health and immunity. High levels of cortisol are linked to a greater risk of high blood pressure, heart disease, and much more. High cortisol may or may not affect how you respond to the COVID vaccine, and how cortisol status affects immunity is highly individual.

One past flu vaccine study points to some interesting evidence on antibody response and elevated cortisol. The study showed that stress levels two days before and on vaccine day were not associated with poor antibody response. But in the 10 days following vaccine, stress did appear to impact antibody response.

While high cortisol levels weren’t helpful, low cortisol affected antibodies, too. In fact, individual responses can be influenced by differences in HPA-axis function.

Have a health issue or concerned about a hormone imbalance? After a COVID vaccine, there’s a way to check your response

Hormone imbalance after a COVID vaccine- lab draw to check immune response

Unfortunately, about 2 to 10% of the healthy population doesn’t build sufficient antibodies to vaccinations due to a number of factors. Those 65 and older may not have as robust of a response because of age. Also, some conditions can also limit or blunt a response. The decision to get any vaccine, or if you are at risk for a low response, is individual and something only you and your provider can decide.

But, if you and your healthcare team have concerns, there a way to check your response to the COVID vaccine. For those who haven’t contracted the virus before, this is simple. Ask your physician or ARNP to have blood drawn and tested for antibodies to COVID-19 (SARS-CoV-2). (Many blood banks are also offering this test free if you donate blood.) If you haven’t had COVID but your results show antibodies, you can rest assured that your body responded to the vaccine. If you were COVID-positive in the past, the results get convoluted: are the antibodies from your past infection or vaccine?

Ideally, to check your vaccine response, you’ll want to wait about a month after your second shot to test for antibodies. Why so long? Your adaptive immune system, which we talked about above, is what helps your body produce antibodies and create memory–and it takes time for it to build a robust response.

Final words on hormone imbalance after a COVID vaccine

Couple shopping in masks

The idea of a hormone imbalance after a COVID vaccine (or any other) can be upsetting or cause anxiety. But research on our response to vaccines doesn’t point to them as a cause for specific or widespread hormone imbalances. However, our hormones can and do affect our vaccine response.

As with any personal health and medical decision, talking things over with your healthcare team is a good idea. They’re familiar with your personal medical history and goals and can help you evaluate the risks of COVID-19 versus the risks and benefits of a COVID vaccine.