Cautiously Optimistic on the Vaccine

As a COVID-19 vaccine looks to be round the corner, how is the “race to roll it out everywhere” looking, asks Tim Harford. First up, he points out the worry that the tremendous desire to have a vaccine asap may be circumventing many of the checks and balances. Pfizer announced 97% effectiveness, not based on peer-reviewed data, but by a press release…

 

Is the world capable of manufacturing hundreds of millions of vaccines in a hurry? Some problems, like those glass vials predicted early, seem to have been solved. But others like dry ice (used to keep things cold, including food) are beginning to see a shortage. There are so many links in the chain, and it’s impossible to be sure every link can scale up.

 

On the cold storage aspect, don’t we already have systems for other vaccines like diphtheria, tetanus, TB, and polio? Yes, but:

“The polio vaccine… needs to be kept at -20C, a temperature achievable by a domestic freezer. But the new Pfizer/BioNTech vaccine needs to be kept at -70C. This ultra-cold chain will not be trivial to maintain.”

 

Solving that ultra-cold chain in turn creates other challenges:

“It would be nice if each vaccine were stored in a single-dose pack. A patient could stroll up to a clinic and get vaccinated at a convenient moment. But the ultra-cold chain will rely on fancy “thermal shippers” storing a thousand doses or more; each glass vial will contain five or 10 doses. Break the seal on a big batch of vaccines and you’re going to want a large number of people coming through the door in short order.”

 

Are we even clear what the vaccines can achieve?

“Will these vaccines make people less infectious or will they simply prevent severe illness?”

Both are good, but preventing the spread would be ideal. The Pfizer paper doesn’t say anything on the topic.

 

Then there’s the challenge with multiple does:

“Not only do we have to figure out who is getting vaccinated when, but we need to get them back again for a second dose 21 days later.”

 

Lastly, we don’t know how long the immunity works:

“Having to vaccinate the entire planet every six months would be quite a performance. Let’s hope the vaccine works for a longer period than that, but for obvious reasons it is far too early to tell.”

 

All very depressing? Harford clarifies his real intention:

“I am excited and optimistic. But this story has a few twists in it yet.”