Flu Vaccine Delays and Shortages

Kids and the Flu

It is time to get your flu vaccine.
Photo by Micah Young/Getty Images

While we now think that flu vaccines are delayed if we don't start seeing them in August, it is important to remember that it wasn't too long ago that experts recommended that the optimal time to get a flu vaccination was in October and November.

It wasn't until the 2006-07 flu season that we started to get updated guidelines for earlier flu vaccinations from the CDC, starting with recommendations to offer flu shots in September for high-risk groups "to avoid missed opportunities for vaccination." The next year, the recommendation for the timing of flu vaccination became "health-care providers should begin offering vaccination soon after vaccine becomes available and if possible by October.

To avoid missed opportunities for vaccination, providers should offer vaccination during routine health-care visits or during hospitalizations whenever vaccine is available."

With over 150 million doses of flu vaccine produced each year, it has been some time since we have seen a true flu vaccine shortage. The fact that more companies are making flu vaccines also helps ensure that shortages don't happen.

Still, most flu vaccine manufacturers use older egg-based technology to grow flu virus strains for vaccine, which is not as reliable nor flexible as many would wish it to be. This is what often leads to flu vaccine delays and shortages - the fact that in some years, the flu virus is simply hard to grow.

Flu Vaccine Delays and Shortages

How common are flu vaccine delays or shortages?

A flu vaccine delay and shortage in 2000 caused a supply of only 26.6 million doses of flu vaccine by October (vs about 76 million the previous year) and about 8 million fewer doses by the end of the season.

The delay and shortage was caused by manufacturers having difficulty growing the H3N3 strain of flu and one fewer flu vaccine manufacturer.

In 2004, Chiron Corporation had its license suspended in the United Kingdom because of 'concerns of possible microbial contamination of product.' Chiron was to produce between 46-48 million doses of influenza vaccine for the United States and so overnight, we had our flu vaccine supply cut in half, leading to true shortages.

An allocation plan that year helped to make sure that flu vaccine got to high-priority providers and people who needed them though.

In 2006, there was a delay in getting flu shots for younger children until November, as Sanofi Pasteur had difficulty producing their flu shots because of poor growth of one of the strains of influenza in the flu shot.

The emergence of H1N1 pandemic strain of influenza led to shortages in 2009. The problem that year was one of timing. The H1N1 flu virus was discovered just as seasonal flu vaccine was starting to be made, which led to a shift in priorities for flu vaccine production. The bigger problem though, in addition to a slow growing H1N1 virus for the vaccine, was an early start to the flu season. When H1N1 vaccine became available in October, it was too late for most people - flu season had already peaked.

After the 2009 H1N1 pandemic, we had several years of a more than ample supply of flu vaccine and on time delivery of our flu vaccine, which likely got most of us spoiled.

It was also why we were all surprised by the production problems that led both GSK and Sanofi to have delays in shipping their flu vaccine in 2014.

And once again in 2015, we will have some flu vaccine delays.

When Should You Get a Flu Shot?

The CDC flu vaccine recommendations state that:

  • Optimally, vaccination should occur before onset of influenza activity in the community.
  • Health care providers should offer vaccination by October, if possible. Vaccination should continue to be offered as long as influenza viruses are circulating.
  • Children aged 6 months through 8 years who require 2 doses should receive their first dose as soon as possible after vaccine becomes available, and the second dose ≥4 weeks later.
  • To avoid missed opportunities for vaccination, providers should offer vaccination to unvaccinated persons aged ≥6 months during routine health care visits and hospitalizations when the vaccine is available.

So basically, get your flu shot as soon as you can and preferably before October.

What's so special about October?

While flu season typically peaks in January or February, it can sometimes peak as early as November or December. If you wait too long to get vaccinated, you might be unprotected when an early flu season hits your area.

But since flu season doesn't usually peak until after December, a month or two of flu vaccine delays shouldn't be a reason to panic. There should still be plenty of time to get your family vaccinated and protected against the flu.

2015-16 Flu Season Supply

Unfortunately, there will be some delays this flu season.

MedImmune, the manufacturers of FluMist are supplying over 16 million doses of flu vaccine this season, but have stated that "We expect customers will begin receiving product in early September and we will continue delivering vaccine throughout the season."

Sanofi Pasteur reports that "Multidose vial orders are anticipated to be filled by the end of September; single use syringes will be supplied at a steady pace through November."

Unlike delays in some other years, this doesn't mean that there won't be any flu vaccine available. It is just that pediatricians won't get their whole flu vaccine shipment at one time. Instead, they will get a little at a time throughout the next few months.

While that type of piecemeal flu vaccine delivery makes it hard to plan flu vaccine clinics, it does help ensure that every pediatrician has some flu vaccine to give their patients. And it should mean that everyone can get vaccinated before the start of flu season.

What You Need to Know about Flu Vaccine Delays and Shortages

Other things to know about flu vaccine delays and shortages include that:

  • Pharmacies often seem to get their shipment of flu vaccine before pediatricians do, especially when there is any kind of delay. This can be because they use multidose vials instead of pre-filled syringes without thimerosal, or that they have ordered from a different manufacturer.
  • Since even in a typical year, flu vaccine for the Vaccines for Children program gets to pediatricians a few weeks after other flu vaccine, this stock will likely also be delayed this year.
  • While they can certainly be frustrating, a flu vaccine delay usually shouldn't mean that your family can't get a flu vaccine. It just may take a little longer than usual.
  • Tamiflu can be an alternative to the flu shot for some high risk children who haven't been vaccinated yet.

Flu vaccine shortages and even delays can mean that some people don't get vaccinated and protected against the flu. This isn't because flu vaccine doesn't eventually become available though, but rather because people give up on trying to get a flu vaccine. Just because flu vaccine becomes available a little later than usual doesn't mean it isn't still a good time to get vaccinated.

If there is a true flu vaccine shortage and your child is in a high risk group for complications from the flu, get a flu vaccine as soon as you can, wherever you can, and be sure you pediatrician puts you on a high priority list to get any vaccine that becomes available.

Unless we have an early flu season, this year's flu vaccine delay shouldn't be more than an inconvenience for most people.


AAP. 2015-16 Influenza Vaccine Supply Update. Updated September 7, 2015

CDC. Prevention and Control of Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices, United States, 2015–16 Influenza Season. MMWR. August 7, 2015 / 64(30);818-825.

O'Leary, Sean T. Influenza Vaccine Delivery Delays from the Perspective of Primary Care Physicians. American Journal of Preventive Medicine, Volume 40, Issue 6, June 2011, Pages 620-624

Zimmerman, Richard K. Shortage of influenza vaccine in 2000–2001: Did it change patient beliefs? American Journal of Preventive Medicine, Volume 24, Issue 4, May 2003, Pages 349-353

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