Patch On, Patch Off

by Haifa Haroon on February 9, 2013

If you’re a parent, you’ve probably had the unfortunate task of holding your child’s limbs down in a doctors office while they got their shots. As a kid, I remember doing this for my brother, watching his eyes well up and feeling guilty for putting him through this.

What if we could bypass this pain without sacrificing our health (or the health of a loved one)? 

Image courtesy of Stanley Leary, Georgia Tech

We may be able to! Several researchers are working on creating vaccine patches – departure from injected vaccines. The patches vary in size, but to give you an idea,you are looking at something approximately the size of a postage stamp, made of silicon and containing anywhere from 36 – 20,000 microscopic projections or “microprojections” (i.e.very small needles!) on its surface.

There are several variations of the vaccine patch under development. In some, the vaccine is coated onto the surface of the microprojections while in others it is located inside them. In order to use a patch, it is pressed onto the skin – on your arm for example – and the vaccine is released to the immune cells below the skin’s surface. In another variation, the microprojections actually penetrate the skin’s surface and dissolve while releasing the vaccine.

Variations of the vaccine patch

Traditionally, vaccines are injected into muscle cells. But studies with mice have shown that delivering the vaccine to the skin can elicit a stronger immune response. This is due to its relatively high number of antigen presenting cells (that is, cells that bind to the molecules (antigens) introduced by the vaccine) and initiate the bodies immune response.

Aren’t there already needle-free vaccines available? 

Yes, there are. The polio, typhoid and rotavirus vaccines are all ingested. However, the oral polio vaccine isn’t used in the United States anymore and the typhoid vaccine is only recommended under special circumstances. There is also a needle-free vaccine for the flu, a nasal-spray, commonly referred to as FluMist. However, FluMist is limited to individuals under 49 years old; preventing older, higher risk populations from benefiting from the needle-less design.

You may have also heard of jet injectors which have been around for several decades. Instead of using a needle, the injector applies pressure to deliver the vaccine through the skin and into muscle tissue. However, the FDA has only approved the jet injector for the mumps, measles and rubella (MMR) vaccine. Additionally, traditional jet injectors are bulky, expensive and have been associated with a high risk of blood-borne disease transmission, making them a less than ideal alternative.

Image courtesy of Rolex Awards/Julian Kingma

So, why is the vaccine patch so great?

  1. Painless. A study confirmed that humans found microneedles 150μm long to be painless. The microneedles on the patches vary in size (e.g. 150-750μm) but are very small compared to syringe needles usually used for vaccine delivery, which are approximately one inch long. This would make the vaccination process go much smoother, especially with young children. It may also be beneficial to adults who are squeamish around needles and therefore may usually opt out of vaccinations and thus put themselves at an increased risk of infection.
  1. Do it yourself. There are a few different versions of the vaccine patch, but they can all be self-applied by hand or with an applicator. This is a significant feature of the vaccine, because it could be picked up at the pharmacy or delivered to your home, instead of requiring a physician visit. It would also be beneficial in developing countries as it would reduce the need for training health care workers as well as reduce the risk of improper injections.
  1. Cheaper. Each dose of the patch could be made for less than $1, which is lower than the production costs of traditional vaccines. This may be partly attributable to the reduced vaccine concentration necessary to produce a strong immune response when applying the vaccine to the skin instead of the muscle. Either way, this would make necessary vaccines much more accessible in developing countries.
  1. No Cold Chain. In some designs of the patch, the vaccine is present in a dried form and thus does not require close temperature monitoring to ensure its long term effectiveness. This is advantageous especially in developing countries where there may be unreliable electricity and long commutes between health care facilities, increasing the risk of breaking the cold-chain and thus rendering the vaccine ineffective.

What’s the hold up?

Although, HPV (human papillomavirus) and influenza vaccine patches have been tested on mice with promising results, there haven’t been any clinical trials. In 2010, the National Institutes of Health (NIH) granted $10 million to several research groups to continue developing vaccine patches for the flu. Merck, the pharmaceutical company responsible for the HPV vaccine, Gardasil, has awarded funds to a separate research group, allowing them to begin conducting clinical trials to test the flu and HPV vaccine patches.

The Bottom Line

Vaccine patches aren’t going to be on the market anytime soon, but when they are available, they’ll have the potential to make a huge impact on mass vaccinations and thus infectious disease transmission – especially in developing countries.

David Reedy February 10, 2013 at 6:34 am

The level of funding seems quite low. A flu shot costs about $25 and perhaps 100 million Americans a year get one. If the patch costs $1 or even $5 that’s a $2 billion or more savings. Is there opposition from pharma or drugstores behind the scenes or are there other issues that are in play?

Haifa Haroon February 10, 2013 at 12:31 pm

Hi David,

I didn’t get a sense that there was any opposition. One of the research groups I referred to is based in Australia and they’ve founded a company (Vaxxas) to devote to this new technology. They received approximately $15 million from their investors. They also received funding from Merck but the amount hasn’t been disclosed. It’s an upfront fee and then continued funding for research.

The other research lab is working with the CDC, Emory and PATH (non-profit global health organization). In addition to the NIH award, they’ve also received funding from the WHO and the Grand Challenges in Global Health initiative (created by the Gates Foundation). I don’t think the WHO amount was disclosed but through Grand Challenges, they would have received at least $200,000 with the opportunity for a $1million grant if they were successful.

I hope this clarifies the funding aspect a bit. I apologize for not adding it to the post!

Hillary February 10, 2013 at 1:48 pm

Additionally, they may choose to markup the patch for American markets. I’m willing to bet some good money that parents would be willing to fork over the cost of an injection (or even a few bucks extra) to not deal with a screaming kid.

Haifa Haroon February 10, 2013 at 3:13 pm

I agree. I think the reduced production costs may be more beneficial to organizations like UNICEF that rely on low cost vaccines.

P.S. Thanks for reading!

Virginia Levin February 11, 2013 at 10:52 am

Perhaps the answer is obvious but would be interested to know the reasoning behind the rejection of the oral polio vaccine in U.S..
Some education in parenting surely would prevent what I believe is a built up in the mind that “this is going to hurt”. But then again let’s hear it for patches especially for developing countries. Your blog is well written and convincing.

Haifa Haroon February 11, 2013 at 1:43 pm

Hi Virginia,

Thank you so much for your feedback! The oral polio vaccine (OPV), although very effective, is also associated with small risk of contracting the disease – referred to as vaccine-derived polio (VDP). While in use, there were a few cases of VDP in the US every year. In contrast to the OPV, the currently recommended vaccine, IPV, uses an inactive form of the poliovirus, which cannot replicate and cause disease.

However, OPV is still used in other countries because it’s a more cost-effective option.

Haifa

Angela February 12, 2013 at 8:17 am

Very interesting post! Having just spent about a month in hospital, where I was being poked with syringes every day, I can’t wait for alternatives to materialise… Usually, as with all novel developments in medicine, there are debates around their benefits and drawbacks. Am wondering whether there are any critics of the patch method (other than those who are generally opposed to vaccines) or whether the benefits are so clear that people are just waiting for the results of the clinical trials.

Haifa Haroon February 13, 2013 at 9:51 pm

Hi Angela,

Apologies for the late reply! I haven’t seen any critics yet, but that’s probably because they haven’t done any clinical trials yet, which really is a drawback itself. I’m sure we’ll hear some debate in the near future. One problem I see is home vaccinations – especially with children. I don’t expect this to happen only because people may forget to vaccinate their children at the appropriate intervals and to ensure proper vaccination and accurate records, this would still be done in a physicians office – but with less tears!

Thank you for reading!

Haifa

Anne February 15, 2013 at 3:52 pm

Great post! As a parent and a local public health practitioner, I can’t wait!

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