Have you ever received a vaccine and felt its effects that night or the following day? Inflammation, fevers, and body aches are signs that your immune system is leaping into action. However, some small studies show that vaccines — including the COVID-19 vaccine — may lead to arthritis symptoms.

In rare cases, people with rheumatoid arthritis (RA) may experience flares after receiving their COVID-19 vaccine. Some small case reports have also found that infection with SARS-CoV-2, the virus that causes COVID-19, can trigger RA.

Doctors and researchers are constantly discovering new information on the connection between COVID-19 vaccines and RA. This article summarizes what we currently know about this connection and what it means for you or a loved one living with RA. With the updated COVID-19 booster vaccine now available, our knowledge on the subject may continue to change.

The New Monovalent COVID-19 Vaccines

The U.S. Food and Drug Administration (FDA) has approved a new round of updated messenger RNA (mRNA) COVID-19 vaccines (2023-2024 formula) for everyone older than 6 months of age. These new versions of the Moderna and Pfizer vaccines are recommended by the Centers for Disease Control and Prevention (CDC).

The previous round of mRNA vaccines were bivalent, meaning they contained blueprints of spike proteins found in two different versions of the virus that causes COVID-19. These new vaccines are monovalent — they contain the blueprints of a single variant, called Omicron variant XBB.1.5 and nicknamed “Kraken.”

Health experts have identified XBB.1.5 as being highly transmissible and contagious. People who’ve received previous vaccinations or previously had COVID-19 have still been infected with this newer variant.

Who Should Get the New Vaccine?

Everyone aged 5 and up is eligible for one dose of the new vaccine as long as it’s been at least 2 months since their last vaccination. Infants aged 6 months to children up to 4 years old may receive more than one dose of the new vaccine, depending on their vaccination status. Additionally, those in this age group (6 months to 4 years) who haven’t been vaccinated can get three shots of the Pfizer COVID-19 vaccine or two shots of the Moderna COVID-19 vaccine.

People who are moderately or severely immunocompromised (have weakened immune systems) should also receive the new vaccine. The CDC cautions that these people are “at increased risk of severe COVID-19 illness and death.”

Are the New Vaccines Safe?

The FDA based its approval of the new mRNA vaccines on the safety and effectiveness of previous versions, which were manufactured in the same way as the new round. Per the CDC, millions of Americans have received COVID-19 vaccines “under the most intense safety monitoring program in U.S. history.”

The FDA noted that the benefits of receiving the vaccine outweigh any risks. Potential side effects — both common and rare but serious — are similar to those of previous versions of the vaccine. Common side effects are generally similar to flu symptoms, including temporary fever, chills, aches, and fatigue, along with irritation or soreness at the injection site.

COVID-19 Vaccines May Contribute to Arthritis Symptoms

Vaccines teach our immune systems how to fight off viruses to help prevent severe infections. The COVID-19 vaccine triggers, just like other vaccines, a bodywide immune system reaction. This is why you may experience side effects like fever, joint and muscle aches and pains, fatigue, and headaches. All these side effects are signs that the COVID-19 vaccine is working, but it does not mean that the vaccine doesn’t work in people who don’t experience side effects.

Fortunately, these mild side effects will go away on their own within a few hours or days. However, if you feel uncomfortable, you can use over-the-counter (OTC) medications like ibuprofen (Advil, Motrin) or naproxen sodium (Aleve). Your immune system will keep working to build immunity over the next few weeks to protect you from COVID-19 or to develop a milder form of COVID-19.

RA vs. Temporary Vaccine Side Effects

Telling the difference between RA symptoms and the temporary side effects of the COVID-19 vaccine can be difficult. However, it’s important to note the differences between the two.

The pain experienced as a side effect is self-limiting, it goes away by itself after a short period of time and, as noted, OTC medications can help ease the symptoms. Swelling isn’t common as a side effect.

Another rare side effect, but important to mention, is reactive arthritis. Reactive arthritis refers to temporary joint swelling and pain, typically as the result of an infection elsewhere in the body. Studies have found that, in rare cases, COVID-19 vaccines can trigger reactive arthritis. According to Cleveland Clinic, symptoms can last anywhere between three and 12 months — your reactive arthritis may come and go.

On the other hand, RA is an autoimmune disease that will likely last the rest of your life. Your immune system specifically attacks the lining of your joints, leading to inflammation, pain, and swelling. Your doctor or rheumatologist (RA specialist) can use blood and imaging tests to make an RA diagnosis.

RA Flares After a COVID-19 Vaccine Are Uncommon

If you’re living with RA, you likely take extra steps to avoid anything that may trigger a disease flare. Many side effects of the COVID-19 vaccine can look similar to flares, including achy muscles and joints, fatigue, and fever. However, studies show that disease flares may be uncommon after receiving a COVID-19 vaccine. They’re more likely after an infection with a live virus that you catch from another person.

For example, a study from 2021 followed 1,519 participants with arthritis or other musculoskeletal conditions after they received their COVID-19 vaccine. Around one-third of the participants had RA. After vaccination, only 5 percent of the participants with arthritis reported experiencing flares — and only 1.2 percent reported severe flares. On average, flare symptoms developed within five days of vaccination.

The most common symptoms during a flare after COVID-19 vaccination included joint pain, swelling, and increased fatigue. Some study participants also experienced potential vaccine side effects, including pain at the injection site. Overall, the study authors concluded that the COVID-19 vaccine is safe for people with RA and similar diseases.

Joint Inflammation May Be a Complication of the COVID-19 Vaccine

Some small case reports have also found that people who previously haven’t had arthritis might develop it after receiving their COVID-19 vaccine. It’s important to note that these case studies each involved a single person who developed inflammatory arthritis after receiving their COVID-19 vaccine. Doctors and researchers need to run additional studies with more participants to find out whether COVID-19 vaccines can cause arthritis.

RA May Also Occur After COVID-19

Some research suggests that natural infection with the SARS-CoV-2 virus can also lead to arthritis and symptoms of joint inflammation, pain, and swelling.

A case series reported on five women who developed inflammatory arthritis (reactive or RA) after having COVID-19. Four of the five women were diagnosed with inflammatory arthritis within four months of having COVID-19. They were treated with a combination of medications to help control inflammation, including nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids.

Again, it’s important to note that more research is needed to confirm whether COVID-19 causes RA or reactive arthritis.

Talk to Your Doctor About Your COVID-19 Vaccination Schedule

RA can affect your lung health, so it’s best to stay up to date with your vaccinations — including the COVID-19 vaccine. The overall benefits of the vaccine outweigh the potential risks of an RA flare.

Be sure to work closely with your doctors when deciding the best plan and timing for your vaccines. Your primary care physician and rheumatologist can determine when you should receive the COVID-19 vaccine to limit the chances of an RA flare.

According to the American College of Rheumatology, you may also get your COVID-19 vaccine even if you’re currently experiencing a flare. If you’re concerned about potential side effects of the vaccine or have questions about how to manage them when living with RA, your doctor can help as well.

Find Your Team

On myRAteam, the social network for people with rheumatoid arthritis and their loved ones, more than 203,000 members come together to ask questions, give advice, and share their stories with others who understand life with rheumatoid arthritis.

Have you received your updated COVID-19 booster vaccine? Did it affect your arthritis symptoms? Share your experience in the comments below, or start a conversation by posting on your Activities page.