honey bee threats

How much will the new AFB vaccine help honey bees?

AFB vaccine: The queen bee passes her immunity to her offspring through her egg yolks.

Everyone is talking about the new AFB vaccine. A vaccine for bees is a miraculous milestone in honey bee management, but how much will it help?

A vaccine for AFB (American foulbrood) in honey bees is a mind-bending achievement. But will it change the landscape of beekeeping or will colony loss continue unabated? To answer that question, let’s look at how the vaccine works.

How does the queen develop immunity?

To understand how the new AFB vaccine works, you need to know just one thing about the honey bee’s immune system. Simply put, insects do not make antibodies like those in humans and dogs and goats.

Instead, bees have “transgenerational immune priming.” Don’t worry about the offputting name; the idea is simple. It just means that when mom (the queen) develops an immune response to something in her environment, she can pass it on to her kids.

That’s it: the whole thing in a nutshell. The vaccine developers exposed queens to dead AFB bacteria so they could develop natural immunity and pass that immunity to their offspring.

There are no genetic modifications, no mRNA, and no freaky chemicals. The vaccine is even approved for organic agriculture.

How does immunity move from queen to colony?

Well, that’s simple, too. Here is a step-by-step description of the process.

  • Dead AFB bacteria are infused into a solution of sugar water that is fed to nurse bees. The nurse bees are unharmed because the bacteria are dead and, in any case, AFB does not affect adult bees.
  • After eating the dead bacteria, the nurse bees secrete royal jelly from their glands. This royal jelly is contaminated by little bits and pieces of dead AFB.
  • The nurse bees feed this contaminated royal jelly to developing queens.
  • Each queen remains unharmed by this, but her own immune system learns to recognize the contaminant and develops resistance to it.
  • After she digests the royal jelly, both the nutrients and the immunity information are stored in her ovaries and fat bodies.
  • When her fat bodies produce vitellogenin (a protein used to make egg yolks) the immune information moves from the queen into the yolk.
  • The yolk nourishes the baby bee and passes the immunity to the offspring.

That’s crazy cool, right?

How much immunity is passed on and does it last?

According to the research, bees raised by this method have a 30 to 50 percent increase in their resistance to AFB. That may not sound like much but it is a tremendous increase over what occurs naturally. Although field trials are ongoing, it appears the immunity lasts for the life of the queen. However, if the queen dies or stops laying, the colony will need a new vaccinated queen to maintain its immunity.

However, as vicious as the disease is, American foulbrood is not currently the biggest threat to honey bees in North America. Still, for those beekeepers with infected hives, this vaccine may well be a game-changer.

American foulbrood

American foulbrood (Paenibacillus larvae) is a bacterial disease spread by spores. It infects the guts of larval honey bees where it reproduces wildly until the bee gut splits open, releasing millions of new spores. The resulting mess has a molasses-like appearance and smells like death. The new spores spread easily throughout the hive and can survive for decades. 

What causes the most honey bee losses?

According to the USDA, in April-June 2020, US colony losses (in operations with at least 5 hives) due to all diseases totaled just 5.5 percent. That small slice of colony loss includes AFB along with many other diseases such as EFB (European foulbrood), chalkbrood, stonebrood, paralysis virus, Kashmir bee virus, deformed wing virus, sacbrood, IAPV (Israeli acute paralysis virus), and Lake Sinai virus.

But during the same time three-month period in 2020, 43.1 percent of colonies were affected by varroa mites. As you can see, losses from AFB were only a fraction of the 5.5 percent, significantly less than those stressed by varroa mites.

In the next quarter, July-September 2020, 6.1 percent of colonies were lost to those diseases and  55.7 percent of colonies were affected by varroa mites. Unfortunately, colony losses from AFB are an afterthought compared to infection by varroa mites. Varroa mites don’t always kill the colony, but they can weaken them substantially.

Additional causes for colony loss

In addition to diseases and mites, other losses resulted from alternative parasites (such as tracheal mites, nosema, hive beetles, and wax moths), pesticides, queen loss, and miscellaneous mishaps (such as bad weather, starvation, predation, and hive damage).

As you can see from the lists, many of these conditions overlap and it’s often difficult or impossible to assign a category. For example, a queen could die from a viral disease causing the colony to collapse. Do we say the colony died from viral disease or queen loss? It’s not an easy call.

Likewise, did a colony collapse because of varroa mites or the diseases varroa mites carry? Some researchers hope that if we could control the viruses, the honey bees may slowly evolve to live with the mites. Such a breakthrough would buy more time to allow mite resistance to develop naturally.

An AFB vaccine is an outstanding achievement

It is easy to see that American foulbrood is not our biggest problem, at least not right now. However, we must remember that in other times and in other countries, it has been a much larger problem, and it could be again.

AFB outbreaks here at home still happen, and they can be devastating to a beekeeper and to nearby apiaries. There’s no doubt that a vaccination that works is an exceptional achievement.

Hope for future interventions

I think the best news relates to the scientific breakthrough of a bee vaccine. Even if one vaccine doesn’t solve today’s worst problem, perhaps hope for other diseases is on the horizon. Even more exciting is that nearly all egg-laying creatures have vitellogenin, including insects, birds, fish, and, amphibians. That means this technology has the potential to be used over and over in other species.

Already the scientists at Dalan Animal health who developed the AFB vaccine are at work on a similar vaccine for EFB. And after that, who knows? Can a vaccine for viral diseases be far behind?

Honey Bee Suite

About Me

My love of bee science is backed by a bachelor’s degree in Agronomic Crops and a master’s in Environmental Studies. I have written extensively about bees, including a current column in American Bee Journal and past columns in Two Million Blossoms and Bee Craft. In recent years, I’ve taken multiple courses in melittology and made extensive identifications of North American bees for iNaturalist. My master beekeeping certificate issued from U Montana. More here.


  • Your article states, “However, if the queen dies or stops laying, the colony will need a new vaccinated queen to maintain its immunity.” If the queen passes the immunity to her progeny, why is a queen raised from her larvae not also immune?

    • Marisol,

      That’s a good question and I don’t have a good answer. I do know that this type of immunity is not written in the genetics of the bees, so it is not long-lasting. I assume a queen produced from the egg of a vaccinated queen probably has some immunity for herself but not enough to pass on. It likely weakens over time, the way own immunity weakens to things like colds and flu. I know it’s not the exact mechanism, but the results may be similar. Likewise, newborn babies get temporary immunity from their mothers, but it starts to decrease after a few months.

      As I learn more about this, I will try for a better answer.

  • In all my years as a beekeeper (less than a decade, actually) I haven’t seen any AFB or even heard of it being in my area. (So far. Knock on wood. Spit spit.) I do read a lot of advice AGAINST using second-hand equipment. Is this going to be one of those deals where the vaccine makes it easier for that spore-ridden equipment to move around and spread the disease?

    I agree that the big takeaway is the vaccination for bees. I’ve seen way too much Deformed Wing and I hope they can work out a vaccination for that.

    • Roberta,

      I don’t know how things will pan out. After the AFB antibiotics were restricted, I thought there would be an uptick in AFB cases, but I was wrong. I, too, have never had AFB in all my years of beekeeping in this area. I’ve seen it a few times when I was called out to look at an infected hive, but that’s all.

  • Those numbers seem extraordinary – unless I am misunderstanding. In the April-June quarter 43.1% of colonies succumbed to varroa and 5.5% to other diseases – so from an average 100 colonies, there were only 52 colonies left. Then in June-September 55.7% succumbed to varroa and 6.1% to other diseases, so of the 52 colonies only 20 remain. That is, from 100 colonies in April 2020, only 20 made it to September. Are things really that bad in the US?
    Interesting article, as always!

    • Alistair,

      There’s a link to the USDA.pdf in the post, but the data presented is extremely confusing. Sometimes it mentions colony loss, and sometimes it cites colony stress, so the whole thing is hard to read. I think that “stress” assumes that the colony is not strong enough to produce normally, although it might not have completely collapsed. So colonies lost and colonies stressed are not quite the same thing, though they are both bad for productivity.

      I added a sentence to help clarify, so thanks for the question.

  • The fact that humans have decided to develop a vaccine for an insect is mind boggling when you really think about what is going on here. Now, if we could just get that problem of habitat loss under control….

  • I was unable to hear the podcast… find the link. Maybe you can post it here.

    Also, I have recorded a podcast with TheZestPodcast.com that will be aired on Public Radio or their website on Mar 9th

  • Great review of the science behind the vaccine. However, I wonder about the practical application of this new preventative. It is my understanding that it will only be available to commercial beekeepers. As a small scale queen producer selling only a few hundred queens per year am I cut out? It is disturbing to thing that there are gate keepers deciding who will have access. Do you know anything about availability?

    • Fred,

      According to ModernFarmer.com, “The vaccine currently has conditional approval for two years. Dalan plans to release the vaccine to a small number of commercial beekeepers over the 2023 season.” Reading between the lines, I believe that once it gets past conditional approval, then it can be released to anyone.

      I think you should apply for it anyway. Dalan will want to test it over diverse field situations, so I think you have a chance at conditional use. The worst they can do is say no.

      • Rusty, thank you for a great article and for answering to all your commenters so wonderfully. This is a great forum!

        Hi Fred,

        Thanks for your question. We are mainly focused on larger operations in this first year because our vaccine is bottled at 50 doses/vial, so the minimum order is quite large for hobbyists. However, we are interested in working with queen producers who will provide the option of individual vaccinated queens to hobbyists. If you are interested, please feel free to fill out this form and someone will reach out to you: https://share.hsforms.com/1-TaHDJCGQKe9u1nWoeAsXAcq5xd

        With this being said, any beekeeper, big or small is encouraged to inquire through “Contact Us” on our website.

        Thank you!
        Nichole Hoffman
        Operations Manager, Dalan Animal Health

  • So many friends have said of late, “Tell me about this new vaccine that is going to inoculate the bees.” They don’t understand AFB or its relevance (or lack thereof) as you describe, and in their opinion, whatever has been afflicting the girls has now been solved. What is important to me is the process of introducing a vaccine via the queen, and hopefully, this is the beginning of a much more expansive process.

    • Ann,

      Yes, they drive me nuts, too. But donations have dropped as inflation has risen, and I can’t fault people for feeling the pinch. My decision to go with advertising resulted from an either/or conundrum: either I find a way to pay for the site or I shut it down. The ones who have spoken up are in the “shut it down” category. So maybe. I’m still thinking on it.

  • My prediction is that this will cause a lot more AFB. Instead of burning and destroying AFB-infected hives, beekeepers will get a queen that has been inoculated. This will cause her offspring to be immune to the spores already in and on all frames, bottom boards, inner covers, and supers that are part of that hive. That beekeeper will then take a frame of brood, with the AFB spores already in it, and put it in another hive. That hive will get infected with AFB and contaminate more frames and equipment with the disease spores. Instead of burning one or two colonies and equipment to get rid of AFB, that beekeeper will soon have all of their hives and equipment infected with AFB spores. If they sell that equipment to an unsuspecting beekeeper, they will have AFB-infected hives too.

    When a hive gets weak or dies and is robbed, the colonies doing the robbing will be infected with AFB. If these are wild colonies, they will be a source for AFB spores for every beekeeper and other wild colonies within 5 miles.

    This sounds like another very bad idea by the US government.

    • Mark,

      But that same thing was happening when everyone was using Terramycin patties. Some beekeepers always keep patties in their hives. Then, when they sold nucs or when their swarms took off, the spores went with them and infected new colonies. I don’t see much difference.

  • Has anyone heard how much it will cost per hive?

    I think it sounds great. But is the small backyard beekeeper going to be able to afford the medication?

    • Michael,

      It sounds like the queen breeders will sell vaccinated queens directly to beekeepers, so I suspect the price will vary with the breeder. It will be interesting to see how all this plays out.

  • Rusty, thanks for your coverage, and I’m excited to read the rest. I paused in your introduction on this sentence: “The vaccine developers exposed queens to dead AFB bacteria so they could develop natural immunity and pass that immunity to their offspring.” Doesn’t “natural immunity” = immunity developed through the course of an infection? Does being exposed to dead bacteria count?

    • Michael,

      Vaccines can be made of live, dead, or attenuated organisms. I recall that the Salk vaccine used dead polio virus, and was very safe. Sabin used attenuated live virus. It worked better but sometimes initiated a case of polio. Everything is a give-and-take.

      In the extant case, the queens are building a natural immunity to a dead bacteria just by exposure, similar to the way the Salk vaccine worked.

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.