Why 9 months is enough?
By: Marcin Brodziak
Tags: Vaccine Safety, Covid 19

Depending on your media diet, you may hear different things about safety of vaccines. Among some of my skeptical friends and family members Covid-19 vaccines have seen two main safety criticisms: side-effects and duration of the trials.

I wrote about side effects a few days ago (it’s really a high-school math problem) and noticed that — surprisingly — math can go a long way. You have to take time to explain it to people, but when you do they believe you. Most likely because it’s the first argument that “feels” deep — unlike most media scaremongering. Even if people don’t follow the math, if they trust that you understand it, it’s enough to put them at ease.

Below is a write-up of my responses to two other criticisms: development time and short testing time.

How do you develop a vaccine in 25 days?

Moderna vaccine took 25 days to develop and that’s the least important thing about it. For all you should care, it could have taken an hour to develop it. Duration of development is as relevant to the quality of a product, as budget is to the quality of a movie and we’ve all seen a 100M+ blockbuster flop.

Still — it’s an impressive result, so let’s talk about. Normally there’s only a handful of labs interested in solving a given disease. Research into some diseases is funded out of government research funds (always low), philanthropy (hit or miss) and occasionally a speculative business investment. Ultimately there’s only so much business sense in developing a vaccine for ebola or malaria. There’s a little more in HIV. There are piles and piles of money for solving covid.

So almost every lab in the world gave it a shot. Some out of good will, but many out of hope for making good money. If hundreds of labs world-wide in parallel try every possible method known to mankind of developing vaccines, someone will get lucky. Moderna, AstraZeneca and Pfizer did.

Sure, it wasn’t pure luck — they knew what they were doing. But so did hundreds of labs, that we are not hearing about (at least not yet). Total time spent on developing vaccine was man-decades, because every biologist, immunologist, geneticist worked 24/7 from January until March to get this done. It was an informed trial and error very effectively parallelised.

How do you ensure safety in 9 months?

Now the 9 month trials. Can you test anything in 9 months? Duration of the trial is partly a concern, but mostly a red herring. It’s not about duration, but about how many people you recruit to the trial and how quickly they get exposed to the virus.

Let’s consider ebola — it’s a very deadly disease, with 25–90% fatality rate. It’s contagious when symptomatic and symptoms are fairly easy to recognise, including vomiting and coughing blood. It’s unlikely you’ll ever contact Ebola, unless you’re 1) in the region when it occasionally erupts, 2) you have direct contact with someone with symptoms and 3) you exchange bodily fluids or blood with such infected person. So to test an ebola vaccine you have very limited set of people you can test it on and such tests will (naturally) take years.

If you have a disease that spreads easily, say through the air, everyone is at risk and there’s plenty of volunteers to test the vaccine on — tests will go much, much faster. So a global pandemic genuinely speeds up the testing. Also a pandemic of irresponsibility and bad government means more people are at risk, so trials go even faster.

Can you test for long-term side effects in a short trial?

A six months trial cannot test for long-term consequences of a vaccine. Like what happens 5 years after you’ve got a shot. That’s true, but this argument works both ways — you have no clue what the long-term 5 years consequences of getting covid are. And for all I know, there’s no reason to believe covid is safer than the vaccine.

So in short — take the vaccine. Also talk to your parents, friends, spouses and everyone else who is willing to listen and use every argument you can to convince them that it’s a good thing to do. Because it is.