Whenever a nip of cold is in the air, and coughs and sneezes ring out in public places, you know it’s flu season again. If you live with diabetes, you’re probably being prodded to go get a flu shot and related vaccines.
People with diabetes (PWDs) face a higher riskTrusted Source of severe illness any infection, including influenza. That’s why it is so important that those with diabetes get their flu shot each season — especially during pandemic times when COVID-19 remains a public health threat in particular for people with chronic conditions.
This article will explain more about why PWDs should consider the flu shot each season, when the best time for that vaccination may be, and what possible impacts it may have on blood sugars and diabetes management.
Do all people with diabetes need a flu shot?
The Centers for Disease Control and Prevention (CDC) recommendsTrusted Source that everyone with diabetes get a flu shot. This includes type 1 and type 2 diabetes, LADA (latent autoimmune diagnosis in adults), and gestational diabetes during pregnancy.
Likewise, the American Diabetes Association (ADA) also recommends annual flu shots for all PWDs and their families, as do the other diabetes organizations and medical professional groups.
Contracting the flu can weaken the immune system, leading to fluctuating and higher glucose levels — which puts PWDs at elevated risk for severe infection as well as a higher risk for COVID-19, and its effects on the body. Studies since 2020 have shown largely that PWDs are more likely — even 3 times more likely — to see more severe COVID-19 illness, compared to those without diabetes.
According to the CDC, about 30%Trusted Source of the adults hospitalized with flu in recent seasons lived with a type of diabetes. This 2017 studyTrusted Source states that PWDs are at increased risk for developing severe complications from the flu, and this 2022 research points out that’s even more pronounced for adults 65 years and older who face more severe flu illness if they live with diabetes.
That is why a shot is recommended every year because there’s a different strain of flu circulating every year.
Marina Basina MD, an endocrinologist at Stanford Medlain, said it’s important for everyone with diabetes to get a flu shot because of the higher risk of severe illness and its implications on diabetes management.
“If a person with diabetes gets the flu, it becomes much more difficult to manage blood sugars,” she told Healthline. “Any infection will elevate blood sugars and increase variability in the readings and resistance to insulin.”
She added that flu symptoms can also lead to low blood sugars and dangerous diabetes ketoacidosis (DKA) even when blood sugars are not significantly elevated.
When is flu season?
Timing may vary each season.
But the CDC points out that flu viruses are most common in the United States during the fall and winter months. Influenza activity often begins to increase in October and November. Most of the time, it peaks between December and February — though flu season can go into early May.
The CDC reported that the flu season from Oct. 1, 2018, to May 4, 2019, was actually the longest-stretching one in a decade at that time, starting strong early on before abating and then followed by another strain of flu kicking in later in the season.
Of course, with COVID-19, the 2020 and 2021 seasons saw unusually low flu rates because of the increased pandemic precautions and more people getting flu shots.
Many public health experts believe that the 2022-23 flu season will bring more cases of the flu than the United States has seen in recent years.
Is there a preferred flu vaccine type for people with diabetes?
As background, there are several different types of influenza vaccine:
Inactivated influenza vaccine (IIV): This is considered the traditional flu shotTrusted Source, usually given as a shot in the upper arm.
Elderly flu shot: For the older crowd, there are high dose shots, as well as one formulated with an adjuvantTrusted Source, an ingredient that boosts the immune system response to the vaccine.
Recombinant flu vaccine: This vaccine has a short shelf life, so you’re not as likely to see it.
Nose-snort flu vaccine: It’s an alternative called LAIV, which stands for live attenuated influenzaTrusted Source, approved for nonpregnant people 2 to 49 years old without certain underlying medical conditions. Diabetes isn’t specifically listed as one of those underlying conditions, although the listTrusted Source includes “people with weakened immune systems” — which certainly does include PWDs.
Xofluza: Approved by the FDA in the 2018-2019 flu season, this new medication was the first flu antiviral OK’d in almost 20 years. It’s for those 12 years and older who’ve only been showing flu-like symptoms for a maximum of 48 hours. For the 2019-20 flu season, the FDA expanded the indication for use of Xofluzo to those 12 years or older who are at high risk of developing flu-related complications, such as those with diabetes.
Despite all of the info above, the CDC advises that PWDs should get injectable dead-virus fluTrusted SourceTrusted SourcevTrusted SourceaTrusted SourcecTrusted SourcecTrusted SourceiTrusted SourcenTrusted SourceaTrusted SourcetTrusted SourceiTrusted SourceoTrusted SourcenTrusted SourcesTrusted Source, thanks to the “long-established safety record” for this kind of vaccination in people with diabetes.
Will a flu shot raise my blood sugar?
It might.
Your arm often aches right after getting a flu shot, because that special vaccine liquid has gone right into your muscle. Until it’s fully absorbed, any kind of pain can cause your blood sugar to spike.
The body’s immune system may be reacting to the vaccine. This initial burst of immune system response causes inflammation from the antigen reaction, and that can trigger a blood sugar spike the same way illnesses do.
The flu can cause your body to release the stress hormones adrenalin or cortisol, which reduce the effectiveness of insulin, meaning you might see higher glucose levels as a result.
There is little actual research on how flu shots can lead to higher blood sugars.
According to the national vaccine safety monitoring database called the Vaccine Adverse Effect Reporting SystemTrusted Source, there have been more than 361 reports of hyperglycemia after a flu shot. This 2022 study included 34 adults with diabetes during the 2018 to 2020 flu seasons, examining their blood sugars in the first 24 hours after they’d gotten a flu shot. Higher blood sugars were found in the first day after the flu shot and returned to pre-vaccination levels by the second day.
Aside from that research, only one other case report highlights higher blood sugars after the flu shot. This 2018 research analysis articleTrusted Source mentions a 41-year-old man with type 2 diabetes, who reported “feeling fatigued and groggy” within 2 hours of a flu shot and having a blood sugar of 264 milligrams per deciliter (mg/dL) about 6 hours later.
That person’s healthcare team could not pinpoint a specific reason for the glucose rise, nor did they indicate it was caused directly by the flu shot itself.
Analyzing that example, the study authorsTrusted Source stated: “The purpose of this case report is to alert healthcare professionals about this potential effect, which is not described in vaccine package inserts or commonly used drug databases. We agree with the vaccination recommendations for people with diabetes and believe that the benefit outweighs the risk of transient, acute hyperglycemia. Patient knowledge and involvement remain the cornerstones of diabetes management. Therefore, it is important to educate patients and alleviate concerns that may arise during their routine (blood sugar management), while emphasizing the importance of vaccines.”
The study authors continued, “We do not recommend changes in pharmacotherapy or SMBG frequency after vaccination because such changes would place an unnecessary burden on patients. Our hope is that future research may shed more light on this phenomenon and enhance understanding vaccination in people with diabetes for both patients and healthcare professionals.”
