The best-case scenario is for a future ATZ vaccine. Another, let’s call it MDN, cannot warm above -20 Celsius (-4 Fahrenheit) between manufacturing plant and the syringe. This is usable in almost every part of every First World country, because most refrigerators’ freezers can handle that. So, we can transport it in cold storage, in a refrigerated truck or refrigerated shipping container from the manufacturing plant to the seaport or airport. The refrigeration unit requires power while on its way to the ship or plane, and continuous power on the vessel. None of this can be ordered from Amazon or Ebay.
Speed is important, as is security, as is continuous temperature regulation for MDN. Most pharmaceuticals are shipped via passenger airline flights, but their schedules are severely disrupted. Certainty will require cargo flights or ocean containers for intercontinental shipments. The old stand-by, dry ice, has limited use on aircraft because it is solid carbon dioxide. The solid sublimates directly to gas, which is dangerous to the crew. Individual insulated boxes will require continuous monitoring for temperature and leaks.
MDN is delicate, as it is principally RNA, which falls apart under little provocation. It also is an artificial thing that doesn’t self-replicate. It’s a set of instructions for the body to create a defense against some weakness in the virus, such as a protein spike. That’s a two-step process, because the instruction actually causes the body to create just the protein spike, necessary for the virus to enter a cell, but harmless without the rest of the virus attached. Step two is the body’s immune system recognizing the protein spike as a potential threat and creating specialized cells to block or destroy the spike.
In manufacturing MDN, it can’t be allowed to rise above -20C. The manufacturing has to be done under freezing conditions. The delicate RNA can’t be treated roughly or it falls apart. Think of threading a needle while doing jumping jacks, standing on a hammock in a snowstorm. We know how to do this, and will do it well. The vials have to be filled while still doing jumping jacks and packed into cases of 200 or 1,000 vials. The cases then cannot be opened to the atmosphere for more than one minute at a time, likely once a day.
As soon as the cases leave the manufacturing plant in a refrigerated truck or container, they are at the mercy of strong forces, such as curious export inspectors who just want to take a peek. Or thieves thinking they can steal vaccines that will still be worth something. Or traffic accidents, or malfunctioning cranes, or longshoremen on strike, and the possibilities are limited only by imagination.
For international shipment, the cases are loaded onto a vessel, air or sea, where each chance to drop the case is a chance to ruin up to five thousand doses. They are loaded as quickly as possible into vessels and hooked up to continuous power for refrigeration. Temperature is monitored continuously throughout the trip. In the Western world, this is do-able. In Third World countries, it probably isn’t.
For in-country shipments the risks are far fewer but still substantial. In the US, Canada, Australia and Japan, with modern transportation systems, it can make sense to dispatch a security guard with a shipment of half a million doses headed for a distribution center. Not so much for six vials, thirty doses, going to an assisted living center.
Each point of vaccination will be slightly different, but with MDN there will be some similarities. Once removed from refrigeration, the vaccine has a short life expectancy. There will not be repeated warming and cooling, meaning that the patients need to show up at regular intervals. A fairly rigid appointment system is needed, with patients scheduling about thirty minutes each. The person giving injections does nothing else until she/he runs out of vaccine doses. Appointments are made two days in advance and sufficient vaccine for that day is delivered before opening time, with minimum buffer.
A medical history is obtained to pinpoint any possible problems, and to provide data for epidemiologists post-injection. That’s how we find out that, say, patients in their thirties today who had mumps between ages of seven and ten did not acquire immunity at the same rate as other patients. The injection is given, noting patient vitals, lot number, time and date and anything unusual. Initially I would tell a patient to wait 20 minutes, report any symptoms, and if all is OK, leave. Less or more time might prove appropriate. We’ll be learning as we go.
Follow up with random sample phone calls at 24 hours and one week. Each vaccinating location will have a miniature crowd-control problem, with social distancing and masks required, and minimum mingling of patients. Leftover doses may well be worthless. Our desire to automate will work against us here. We can automate parts of this, but the appointments will need a human eye until we get them right.
All of this depends on information about a virus that didn’t exist until about a year ago. Some of this will be wrong, and some will need changes.
