COVID Transmissions for 9-11-2020

Getting the vaccines to the people

Sep 11, 2020

Good morning! It has been 298 days since the first documented human case of COVID-19. It has also been 19 years since September 11, 2001. While I reflect on the horrors of that day, it’s also striking me just how many disasters the 21st century has known. I hope the next 80 years have better things in store.

Today I’m finishing off the series on vaccine formulation and delivery. Short headlines section, though. I heard that Bob Woodward has some tapes about Trump downplaying COVID, but I don’t think that’s a surprise to anyone, nor do I think it terribly impacts the current situation, so that’s all I’ll say about it.

As usual, bolded terms are linked to the running newsletter glossary.

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Now, let’s talk COVID.

Delays in medical care due to COVID-19

In the past we have discussed the backlog of surgeries that COVID-19 has caused to pile up in Canada. A similar situation has arisen in the US with delay of care; this week in the CDC’s Morbidity and Mortality Weekly Report, a study was published revealing that 41% of Americans have delayed medical care due to COVID-19 concerns: https://www.cdc.gov/mmwr/volumes/69/wr/mm6936a4.htm

What am I doing to cope with the pandemic? This:

Day Job

Tomorrow I meet my new restructured team. That’s going to be interesting.

Vaccine formulation, delivery, and design, Part 3

Image is a stock photo of a row of glass vaccine vials that I took from the CDC. Yes, I used it again. I like it.

I wanted to close out the series on vaccine formulation and design by discussing how vaccines actually get to market. In previous pieces in this series, we talked about how vaccines are designed to implement an effective immune response. This piece is going to be a little different; we’re going to talk about how vaccines can be formulated to make it to market in a way that keeps them stable and effective.

One thing that is a theme in all the vaccines that we walked through in the last two articles was that vaccines are biological products. They are not chemicals like the drugs in your medicine cabinet; they are made of the same stuff that living things are made of. This means that they are much more likely to spoil.

Yes, the drugs in your medicine cabinet have expiration dates and they can go bad, but they go bad usually for more inherent chemical or mechanical reasons. The starch that makes the substance of the pill loses cohesion and falls apart, or the active ingredient slowly breaks down because heat, time, or ambient radiation starts to mess with its chemical bonds. Small molecules are a lot more resilient to this kind of thing than big, messy, biological particles.

Vaccines, as “biologics,” the general term for any medicine made from biological entities, are more prone to decay, spoilage, and even contamination with other biological entities that might want to eat them. The spoilage characteristics of these products can be a lot more like those of the foods we eat than like resilient, shelf-stable pills.

As a result, it is important to formulate vaccines in a way that makes them resistant to spoilage. Many techniques are used to manage this. One thing that you may have heard about is a shortage of medical-grade glass that could interfere with vaccine supply, covered here as an example: https://www.businessinsider.com/coronavirus-vaccine-glass-vial-shortage-could-delay-global-rollout-2020-5

If I were reading this, I’d be wondering why we need to use glass. Why not plastic vials? The fact is, medical glass is temperature resistant to a greater degree than plastic and ships better. These mechanical characteristics make it superior for making sure that a vaccine survives shipping to its destination.

A lot of the problems that arise in vaccine delivery are similar logistic issues; the “last mile problem” is often the biggest problem for a vaccine. For example, another issue with vaccine delivery is the need for a continuous “cold chain” for certain vaccines. Specifically, these vaccines need to be refrigerated consistently from factory to syringe so that they do not spoil.

The need for cold chain transportation is common with many vaccines, and it is a huge global health issue. There are a lot of parts of the world where refrigeration is not universally available at all medical clinics. Furthermore, even in developed countries where such technology is ubiquitous, it’s expensive to get refrigerated transport and to keep that cold chain unbroken. It’s a lot cheaper to have a vaccine formulation that can be delivered without refrigeration, and it’s easier to deliver to areas where refrigeration is not available.

You may remember that some days ago, I shared a headline about the Russian vaccine study. That study, called Sputnik-V, looked at two vaccine preparations. One was a frozen vaccine that would have required cold chain transportation. The other was “lyophilized,” a process that can make biologic entities shelf-stable. This was smart; the Russian developers were looking to determine if their vaccine, a viral vector vaccine, could be prepared in a way that didn’t require refrigeration. They were trying to solve the problem that I’ve just described.

Lyophilization is something that you’ve heard of before, by the way. In terms that don’t obfuscate, it’s called freeze-drying. Lyophilization of fragile biologics helps keep them shelf-stable without refrigeration and is very common. The smallpox vaccine was often lyophilized to make it shelf-stable, for example. This formulation of the vaccine was something that could be deployed globally at little expense, and the ability to do that was extremely important for the eradication of smallpox. It may also be important for the management of COVID-19.

There is a lot more to vaccine manufacture that I’m not covering here, much of which I simply don’t know the first thing about. What I do know is that a lot of care and thought goes into deploying a vaccine, and the COVID-19 vaccine(s) that make it to market will be no different. In fact, we are about to witness the most rapid large-scale vaccine deployment program in history. How we make the vaccine is going to have a huge impact on how expensive, and how effective, that program is going to be.

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