Anaphylaxis after vaccines is a well known side effect, but just how common is it?
Anaphylaxis After Vaccines
Since it is listed as a possible reaction to nearly all vaccines and it can be life-threatening, anaphylaxis must be fairly common, right?
“Vaccine providers should be familiar with identifying immediate-type allergic reactions, including anaphylaxis, and be competent in treating these events at the time of vaccine administration. Providers should also have a plan in place to contact emergency medical services immediately in the event of a severe acute vaccine reaction.”
Preventing and Managing Adverse Reactions
After all, pediatricians even get warned to have a plan in place and to be prepared to treat children just in case they develop anaphylaxis after getting their vaccines.
Epi Is Readily Available to Treat Most Kids with Anaphylaxis After Vaccines
Still, most probably have never had to.
“Any medication can cause a severe allergic reaction. Such reactions to a vaccine are estimated at about 1 in a million doses, and would happen within a few minutes to a few hours after the vaccination.”
Possible Side-effects from Vaccines
And that’s because anaphylaxis after vaccines is very rare.
Anaphylaxis After Vaccines is Rarely Fatal
And suprisingly, it is even more rare for these cases to be fatal!
“All 30 patients with anaphylaxis survived (9 reports specified anaphylaxis, and we classified another 21 as probable cases, based on compatible clinical features, including respiratory and skin symptoms within 4 hours after vaccination). In half of 22 detailed reports, symptoms developed within 15 minutes after vaccination.”
Wise et al on Postlicensure Safety Surveillance for Varicella Vaccine
But that study just looked at the chicken pox vaccine and used VAERS, so we have to be concerned about under-reporting, right? Well, not necessarily. Under-reporting likely isn’t a big problem for serious reactions.
Anyway, that’s not the only study…
“We identified 33 confirmed vaccine-triggered anaphylaxis cases that occurred after 25,173,965 vaccine doses. The rate of anaphylaxis was 1.31 (95% CI, 0.90-1.84) per million vaccine doses.”
McNeill et al on Risk of anaphylaxis after vaccination in children and adults
The McNeill study used the Vaccine Safety Datalink, which unlike VAERS, is not a passive reporting system. So there is no concern about underreporting.
And like the Wise study, there were no deaths among these vaccine-triggered anaphylaxis cases.
“Fatalities from vaccine-induced anaphylaxis are exceedingly rare.”
Adverse reactions to vaccines practice parameter 2012 update
Similarly, a study in the UK found rare reports of anaphylaxis after vaccines in children and all those children made a full recovery.
Parents should understand that while anaphylaxis is a known side effect to getting a vaccine, it is extremely rare, and can usually be treated. This once again reinforces that vaccines are safe!
We sometimes hear that folks are going to skip their yearly flu vaccine because they don’t believe in flu shots, they never get sick, or they think that flu shots don’t work or are dangerous.
Some nurses and doctors are refusing to get a flu shot and have to wear masks at work.
Flu vaccines are safe and have many benefits, even if they aren’t any where near 100% effective.
So are there any legitimate reasons to skip a flu shot?
Of course.
In fact, three very good reasons to skip a flu shot include:
being younger than 6 months of age
having a severe allergic reaction (e.g., anaphylaxis) after a previous dose of flu vaccine or to any component of the flu vaccine
and, uh…
Actually, although folks might have many of bad excuses, there are only two good reasons to skip a flu shot…
So, infants who aren’t old enough to be vaccinated yet, and anyone who has had a life-threatening reaction to a previous dose.
Additional precautions, but not true contraindications, do including having had Guillain-Barré syndrome <6 weeks after a previous dose of influenza vaccine and having a moderate or severe acute illness with or without fever when you are planning to get vaccinated.
Even if you have had a severe reaction to eggs, you can still get a flu shot. Just get it get it in an inpatient or outpatient medical setting (such as a hospital, clinic, health department, or physician’s office), so that you can be supervised by a health care provider who is able to recognize and manage severe allergic reactions.
Are you skipping the flu shot because you never get sick? How lucky do you feel this year? Don’t continue to gamble that you won’t get the flu. Increase your chances of staying well by getting a flu shot, the best way to avoid the flu.
Are you still worried about your child’s egg allergy and getting them a flu vaccine?
Everyone needs a flu shot. Even kids with egg allergies. Photo by Gabriel Saldana (CC BY-SA 2.0)
That’s not surprising, as we once warned people about residual egg proteins in flu vaccines and the possibility of immediate hypersensitivity reactions in those with severe egg allergies.
“Recent studies have shown that even individuals with confirmed egg allergy can safely receive the flu vaccine. The Joint Task Force on Practice Parameters of the American Academy of Allergy Asthma and Immunology and the American College of Allergy Asthma and Immunology as well as the American Academy of Pediatrics state that no special precautions are required for the administration of influenza vaccine to egg-allergic patients no matter how severe the egg allergy.”
Egg Allergy and the Flu Vaccine
In fact, it began to change in 2011, when we got the recommendation that it was okay to give flu shots to people with egg allergies, if they only get hives as their reaction. It was still recommended that those with more severe allergic reactions to eggs “be referred to a physician with expertise in the management of allergic conditions for further risk assessment before receipt of vaccine.”
Before that, we would sometimes do skin testing on high risk egg allergic kids, desensitization, or regular chemoprophylaxis.
In 2013, the recommendation changed so that those with severe allergic reactions to eggs should get their flu shot “by a physician with experience in the recognition and management of severe allergic conditions.”
The recommendations were again modified in 2016, removing the recommendation that egg-allergic flu vaccine recipients be observed for 30 minutes and that those with severe egg allergies “should be vaccinated in an inpatient or outpatient medical setting (including but not necessarily limited to hospitals, clinics, health departments, and physician offices), under the supervision of a health care provider who is able to recognize and manage severe allergic conditions.”
Why the changing advice?
It’s because severe allergic reactions to vaccine are rare (in a million doses rare). And even in the flu vaccines that still use eggs, almost all of the egg protein is removed from the final vaccine. So that residual amount of egg protein is unlikely to trigger an allergic reaction. And that’s what we saw as the recommendations were slowly changed year after year.
Getting a Flu Shot When You Are Allergic to Eggs
And that’s why we have our current recommendations:
Those with a history of egg allergy who only get hives can get any age-appropriate flu vaccine.
Those with a history of egg allergy who have severe reactions, including angioedema, respiratory distress, lightheadedness, recurrent emesis, or who required epinephrine or another emergency medical interventions, can still get any age-appropriate flu vaccine, but they should get it in an inpatient or outpatient medical setting (such as a hospital, clinic, health department, or physician’s office). And the vaccine administration should be supervised by a health care provider who is able to recognize and manage severe allergic reactions.
Those who can eat eggs without reaction can get any age-appropriate flu vaccine.
Do you still have to be observed after getting your flu vaccine if you have an egg allergy?
No postvaccination observation period is recommended specifically for egg-allergic persons.
Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices—United States, 2018–19 Influenza Season
Nope. But that’s likely because although they are rare, reactions might not occur right away.
So yes, you can and you should get a flu vaccine if you are allergic to eggs.
After decades with a single type of flu vaccine – the flu shot – there are now many different kinds of flu vaccines that many of us can choose from. And your choices are not just between the nasal spray flu vaccine vs a flu shot. There are also a lot of different kinds of flu shots available now.
Everyone needs a flu shot. When will you get yours? Photo by Gabriel Saldana (CC BY-SA 2.0)
Having choices is nice.
It would be also be nice to have a little more guidance on what to do with these choices.
It is actually easy to start by asking which one you should get for your kids, as many of these flu vaccine options are only available for adults and seniors.
Flu Vaccine Options
Before you start thinking too long and hard about potential options, keep in mind that you might not have as many options as you think.
“Not all products are likely to be uniformly available in any practice setting or locality. Vaccination should not be delayed in order to obtain a specific product when an appropriate one is already available.”
Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices—United States, 2018–19 Influenza Season
Doctors and clinics might not stock multiple brands or types of flu vaccines, so you might have to get whatever flu vaccine that they have available.
“Within these guidelines and approved indications, where more than one type of vaccine is appropriate and available, no preferential recommendation is made for use of any influenza vaccine product over another.”
Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices—United States, 2018–19 Influenza Season
And that’s okay. In most cases, there haven’t been head to head studies showing that one flu vaccine is better than another.
Flu Vaccine Options for Kids
Still, since these options might be available to you, it is good to know about them.
This year, younger kids, between the ages of 6 months and 3 years, can either get:
FluLaval Quadrilvalent
Fluarix Quadrivalent
Fluzone Quadrivalent Pediatric
While you are unlikely to notice a difference, both FluLaval and Fluarix are given at a 0.5ml dose containing 15 µg of HA per vaccine virus, while Fluzone is given at a 0.25ml dose containing 7.5 µg of HA per vaccine virus. Why the difference? “Safety and reactogenicity were similar between the two vaccines,” even at the different doses.
Basically, these are just different brands of the same type of flu shot.
There are even more options as your kids get older though, including Fluzone Quadrivalent (age three and above), Afluria Quadrivalent or Trivalent (age three and above), Flucelvax Quadrivalent (age four and above), FluLaval and Fluarix.
Of these, some folks wonder if Flucelvax, since it isn’t made in chicken eggs, might be more effective than the others. Remember, one of the things that are thought to make the flu vaccine less effective than most other vaccines is that they are made in eggs, leading to mutations. And there is actually some evidence that those flu vaccines that are not made in eggs might be more effective.
“And the University of Pittsburgh Medical Center is taking that a step further, saying it will only be buying the two egg-free vaccines on the market: Flucelvax and FluBlok. That’s because there is some evidence these two formulations may work better than the older vaccines grown in eggs, said Dr. Richard Zimmerman, who advises the UPMC Influenza Committee.”
Guidance on which flu vaccine to get: Shots for kids, maybe go egg-free
Again, remember that the CDC has made “no preferential recommendation” for one flu vaccine over another. Why not? We don’t have enough information to make that kind of recommendation.
Should parents only ask for Flucelvax? That would only work if they made enough doses for every kid to get vaccinated, which they didn’t. Should you hold out until you can find FluceIvax for your kids? No, since doing that might leave them unvaccinated once flu season hits.
What else should you know about your flu vaccine options? While over 80% of flu vaccines are now thimerosal free, most of these flu vaccines are still available in multi-dose vials with thimerosal.
Also thimerosal free, this year, Flumist is back as an option. It is available for healthy kids who are at least two years old. Although the AAP has issued a preference for flu shots this year, the ACIP says that kids can get either Flumist or a flu shot.
What about if your kids are allergic to eggs?
“Persons who report having had reactions to egg involving symptoms other than urticaria (hives), such as angioedema, respiratory distress, lightheadedness, or recurrent emesis; or who required epinephrine or another emergency medical intervention, may similarly receive any licensed, recommended, and age-appropriate influenza vaccine (i.e., any IIV, RIV4, or LAIV4) that is otherwise appropriate for their health status.”
Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices—United States, 2018–19 Influenza Season
Unless they had a severe allergic reaction to a previous flu vaccine, they can get any available flu vaccine, especially if the previous reaction was only hives or they are able to eat eggs.
What if you want a flu vaccine without aluminum? Take your pick. While it would be safe it was, aluminum is not an ingredient in flu vaccines.
Flu Vaccine Options for Adults
In addition to all of the flu vaccines available for older kids, adults have a few more options:
Afluria Quadrivalent or Trivalent can be given by jet injector to those between the ages of 18 and 64 years
Flublok Quadrivalent – a recombinant flu shot that can be given to those who are at least 18 years old
Fluzone High-Dose – a trivalent flu shot with a higher dose of flu virus antigens (4 times the amount of antigen as a regular flu shot) that is available for seniors who are at least 65 years old
Fluad – a trivalent flu shot with an adjuvant that is available for seniors who are at least 65 years old
Why get a flu vaccine with a jet injector instead of a standard needle? High-pressure jet injectors don’t use needles!
Like FluceIvax, Flublok is not made in chicken eggs. The recombinant hemagglutinin(HA) proteins are made in insect cell lines. Does Flublok work better than egg based flu vaccines? That’s the theory, but again, there is no preference for one of these vaccines over another.
Seniors have even more choices.
Should they get Fluzone High-Dose, Fluad, or one of the other flu vaccines? Both have been shown to be more effective than standard flu vaccines in seniors, but they have not been compared against each other.
“In a Canadian observational study of 282 people aged 65 years and older conducted during the 2011-12 season, Fluad was 63% more effective than regular-dose unadjuvanted flu shots.”
CDC on People 65 Years and Older & Influenza
But neither Fluzone High-Dose nor Fluad are quadrivalent, so only protect against three flu virus strains.
Is there a quadrivalent flu shot for older adults that might work better than standard flu shots?
Yes. FluceIvax and Flublok are non-egg based quadrivalent flu shots that might be more effective than standard flu vaccines.
So are you more confused now that you know you have so many options? Just remember that for most people, the mistake isn’t about choosing the right flu vaccine, it is about not getting vaccinated.
What to Know About Your Flu Vaccine Options
While it might seem like you have a lot more options in a flu vaccine this year and that some might be more effective than others, keep in mind that availability will likely greatly limit these “options.”
And the best flu vaccine is the one that you actually get, as it will be the one that reduces your risk of getting the flu. Missing your chance to get vaccinated and protected because you are waiting for a specific brand or type of flu vaccine isn’t going to help keep the flu away.
