Vaccines, Ear Infections, Chinchillas, and a BandAid

July 14, 2017

What does a chinchilla have to do with vaccines? Ear infections? A Bandaid? It's actually pretty interesting--have a look.

[[{"type":"media","view_mode":"media_crop","fid":"61695","attributes":{"alt":"","class":"media-image media-image-right","id":"media_crop_7409628035327","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"7802","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"height: 212px; width: 300px; float: right;","title":" ","typeof":"foaf:Image"}}]]The title of this article offers an odd assortment of topics, but they are all connected and they do all relate to the broader topic of vaccines.

Answer this first question and the rest will quickly become clear.

We know which bacteria are responsible for most ear infections: Streptococcus pneumoniae, Moraxella catarrhalis, and non-typeable Haemophilus influenzae.

1. Which of the following vaccines has NOT been shown to be of much value in reducing middle ear infections (acute otitis media [AOM]) in children?

A. Prevnar

B. Hib vaccines

C. Influenza vaccines

Answer, discussion, and next question>

The correct answer is B. Hib vaccine (is not effective in reducing pediatric AOM) 

Prevnar, now containing 13 strains, protects against some of the strains of pneumococcus that can cause AOM and has been shown in studies to exert a modest effect in reducing subsequent ear infections and need for PE tubes.

Influenza vaccines also have been shown to reduce the risk of ear infections by reducing the risk of getting the flu which predisposes a child for an ear infection. 

Hib vaccines protect only against the invasive B strain. Most ear infections attributed to H. influenzae were (before the introduction of the Hib vaccines in the 1980s) and still are caused by nontypeable stains of haemophilus, so the answer is B.  The Hib vaccine has no efficacy against the non-typeable strains.

The chinchilla connection

Middle ear infections remain a significant problem for parents and pediatricians and are responsible for millions of antibiotic prescriptions per year. Work is under way to develop a vaccine against nontypeable H. influenzae. Chinchillas seem to be the only animal model used for otitis studies and this new vaccine has been shown to be about 70% effective in this species.  So, now you can see the relation between chinchillas, ear infections, and vaccines. But, BandAids?

[[{"type":"media","view_mode":"media_crop","fid":"61695","attributes":{"alt":"","class":"media-image media-image-right","id":"media_crop_6947883938170","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"7802","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"height: 141px; width: 200px; float: right;","title":" ","typeof":"foaf:Image"}}]]The vaccine in the chinchilla study was administered via a band aid or transdermal patch with microneedles coated with vaccine antigen. Transcutaneous immunization (TCI) makes sense on an immunologic basis. The skin is an immunologically active organ with Langerhans cells that capture and then present antigens to the lymph glands. Sanofi’s intradermal flu vaccine only needs 60% of the antigens used in the intramuscular version of their flu vaccines to achieve the same immune response. 

Given the reduced amount of antigen in the Fluzone intradermal vaccine dose, it stands to reason that side effects might be less vs those after intramuscular administration.   

2. The intradermal influenza vaccine is associated with less of which of the following?

A. Pain

B. Swelling/induration

C. Fever

D. None of the above

Answer and discussion>

The answer is D. None of the above

Per the package insert of the intradermal product:

A. Pain is about the same, 51% versus 53%. 

B. Swelling and induration are more with the intradermal product, roughly 76% versus 13% with the shot. 

C. Fever is the same (4% versus 3%). 

D. Thus, none of the above.

The intradermal shot is actually more reactogenic than the IM shot, speaking to the immune response generated by the dermis.

Most children, and a fair number of adults as well, have some degree of needle phobia so a patch approach would be very appealing to these groups. The stratum corneum serves as an effective barrier to entry of outside agents.  The microneedles penetrate this layer in a painless process. TCI has been shown to be effective in murine and primate models as well.