Dr. Farber’s blog part III

RSV Vaccine/Antibody

Today, I will talk about RSV. RSV stands for Respiratory Syncytial Virus, the most common, but not the only, cause of wheezing and difficulty breathing in infants.

We do not have a specific treatment for this disease, which is why we often do not test for it routinely in the office when we suspect it; confirming RSV will usually not change management. I have been waiting for protection against RSV for a long-time. In my career, this has been the most common viral cause of hospitalization and serious illness, well above other diseases which had earlier vaccines developed, such as hepatitis A. However, there have been technical problems creating a vaccine. Similarly, we still do not have vaccines against other common diseases such as AIDS or malaria.

I don’t want to give ammunition for anti-vaxxers, but in the interests of historical accuracy, I must disclose that there was a vaccine against RSV released in the 1960s. However, that vaccine was not studied in anywhere near the number of children today’s vaccines are, and it caused significant side effects, and was withdrawn. The safety data on current products are orders of magnitude beyond those back then.
I am going to get technical yet again. Vaccines cause the body to produce antibodies, and we do have a vaccine against RSV, but that vaccine is only for adults. The current new product for children, Nirsevimab (Beyfortus), is actually a monoclonal antibody (which is why the name ends in mab). This is an artificial, but safe, antibody that helps fight off an infection even without support from the body itself. (People, include the staff at ALL Pediatrics, will no doubt refer to it incorrectly as a vaccine from time to time, if only from force of habit).

We already have an antibody product, best known as Synagis, against RSV for several years. It is effective, but expensive, requires five monthly injections, and is reserved for high-risk children who would benefit the most. The current monoclonal only requires one injection per season, and is more effective. It is recommended for children who will be 8 months of age or younger during RSV season, which is typically around September to March.

It is not given to older children, because they usually have some natural immunity from exposure in the real world, and the disease is typically mild, a nuisance rather than serious, with nowhere near the hospitalization/death rate seen with, for example, flu. In addition, as stated, this is not a vaccine. It provides antibodies, but does not stimulate the body to make them on their own, so once they are cleared from the body you are back to square one, without long-term protection.

Eventually, we will have an actual vaccine for infants; I am hopeful this will arrive in the next two years. In the interim, we have the antibody, but there is a major snag with its use this year: there is under-production. As a result, there is only antibody for children under 11 pounds, and supplies are limited. Furthermore, it is expensive, over $500 for a dose, and many insurance companies are dragging their feet about paying for it. As such, we will be able to offer a very small number of infants the antibody when we have it in stock.

In summary, this antibody will be a breakthrough, but for the vast majority of infants, it will have to wait until next year, when there will be new batches of antibody, and new batches of infants.

Lastly, there is one other way to protect newborns, and that is for a pregnant woman to receive the previously mentioned vaccine. She will then make antibodies, which can be passed on in the womb. If this is an option for you, please take advantage of it with your obstetrician.