Is It Safe to Get a Flu Shot While Taking MS Drugs? – Everyday Health

Flu, or influenza, vaccines are designed to cause antibodies against the virus to develop in your body about two weeks after you receive the shot, according to the CDC.

Antibodies are proteins created by your immune system that provide protection against infection with the viruses that are used to make vaccine, which varies from year to year based on what research suggests will be the most common during the winter season, the agency says.

The two key types of flu vaccines with implications for people with MS are:

Live-Attenuated Influenza Vaccine This vaccine is made from weakened influenza viruses. These weakened viruses stimulate your immune system to create sufficient antibodies to fight off stronger forms of the virus. In the United States, live-attenuated flu vaccines are available in a nasal spray and are made in an egg-based process, according to the CDC. So if youre allergic to eggs, you should avoid these vaccines, whether you have MS or not.

Inactivated (Killed) Flu Vaccines These are the injections most often called flu shots, the CDC says. They are also known as recombinant flu vaccines. These vaccines arent made using candidate vaccine virus samples. Instead, theyre made synthetically, based on the DNA of naturally occurring flu viruses. They may be made in egg-based manufacturing processes, or using cell-based approaches, according to the CDC.

RELATED: What Is the Difference Between Cold and Flu?

Live and live-attenuated vaccines, including flu vaccines, arent recommended for people with MS who take a disease modifying therapy (DMT), because the vaccines effectiveness may be reduced by these drugs, according to the National MS Society.

In some cases, DMTs may weaken the immune system, meaning those people injected with live vaccines may be at risk for getting sick from the viruses the vaccines are designed to prevent, the society adds.

DMTs include the following injectable medications:

These oral drugs are also DMTs:

And these infused drugs are DMTS:

According to the AAN guidelines, research suggests that Tecfidera, Vumerity, Gilenya, CopaxoneandGlatopa, AvonexandRebif, BetaseronandExtavia, Novantrone, Tysabri, and Aubagio are likely reduce the effectiveness of the live and live-attenuated flu vaccine. This doesnt make the vaccine dangerous it just means that it may not offer as much protection against the flu, Bar-Or says.

However, the DMTs Lemtrada, Mavenclad, Ocrevus, Zeposia, and Mayzent may also weaken your immune system enough that live and live-attenuated vaccines, including the flu vaccine, shouldnt be used or should only be used after taking precautions, the National MS Society advises. This is because even the weakened forms of the virus could make you sick.

For this reason, people with MS taking Lemtrada, or who have recently taken the drug, shouldnt receive any live vaccines, including the flu vaccine, the society says. In addition, people taking Zeposia and Mayzent shouldnt get these vaccines.

People with MS also shouldnt start treatment with Mavenclad until four to six weeks after receiving a live or live-attenuated vaccine. And treatment with Ocrevus shouldnt be initiated until at least four weeks after youve received one of these vaccines.

Like DMTs, B cell therapies used in the treatment of MS including Kesimpta (ofatumumab) and Rituxan (rituximab) may negatively impact the effectiveness of the flu vaccine, according to Bar-Or. These medications are designed to kill immune cells called B cells, which are believed to play a role in the development of brain lesions in people with MS, he says.

By leading to the death of B cells, these drugs can make the vaccine less effective.

The effectiveness of vaccines is typically assessed based on the ability to mount an antibody response, such as anti-flu antibodies, Bar-Or explains. Since antibodies are generated through the activation of B cells, MS treatments that remove these cells result in a substantial decrease in the ability of the vaccine to generate antibodies.

"However, assessing vaccine responses based only the antibody response in patients treated with B cell therapies likely underestimates the utility of the vaccines, since cellular immune responses to the vaccines (which are more important than antibody responses for many vaccines) are likely to be minimally impacted by the B cell therapies," he adds.

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Is It Safe to Get a Flu Shot While Taking MS Drugs? - Everyday Health