COVID Transmissions for 1-28-2021
Novavax works in the UK, but not everywhere
Good morning and welcome to COVID Transmissions.
It has been 438 days since the first documented human case of COVID-19. Time to go into another weekend.
Today, I report on a new vaccine with mixed results depending on what variant is prevalent in the local area. Also, a headline on long-haul COVID-19.
As usual, bolded terms are linked to the running newsletter glossary.
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Now, let’s talk COVID.
Good news and bad news: Novavax
Yesterday we saw the first Phase 3 trial results for the Novavax COVID-19 vaccine. This is a nanoparticle vaccine with a recombinant protein on the surface. In good news, the vaccine efficacy observed in the UK was reported as 89.3% in 15,000 patients, which is nicely in the same range as the mRNA vaccines from Pfizer and Moderna.
The good news basically ends there. In a separate Phase 2b trial in South Africa, where 90% of cases were infected with the B.1.351 lineage of SARS-CoV-2, the vaccine efficacy was 60%. That is very much not what we were looking for, though it is actually still a pretty good vaccine efficacy, all told. The vaccine is far from useless against this new variant.
However, we have a few items to unpack with this. First, 1/3 of the 4400 patients in the trial in South Africa were positive for antibodies against SARS-CoV-2 at baseline. Novavax felt that, given the infection rate in the trial, this indicated that the B.1.351 variant is capable of escaping preexisting immunity to other lineages of SARS-CoV-2. I would like to see more data to agree with their conclusion, but I agree that the possibility definitely exists.
Then we need to think about the vaccine itself. We know that this vaccine was 89.3% effective in the UK, and far less so in the South African trial. It could be that there is some other factor at play here—perhaps in the South African trial, the lower sample size distorted the results slightly? I don’t think that’s very likely, but it’s a possibility. The confidence interval for the vaccine efficacy in the trial does range from 19.9% to 80.1%, so there’s a wide possibility of variation. 60% might not quite be the right number. For comparison, the UK trial had a confidence interval from 75.2% to 95.4%, a much tighter window.
The likelihood here is that the predominant variant in South Africa is the reason for the lowered efficacy. 90% of infections in the trial were due to this variant. It appears to be at least somewhat immunologically distinct from other lineages of SARS-CoV-2. Given more opportunity to mutate and differentiate itself, this variant could become a separate strain.
Another issue is that this is the first vaccine efficacy result that we have in a population where this variant is prevalent. While we have data on the ability of antibodies raised against the Moderna vaccine to neutralize this variant, that isn’t the same as real vaccine efficacy. The immune response is more than just antibodies; we do not know for sure that antibodies are a correlate of protection. It is entirely possible—maybe even likely—that the other vaccines are also compromised against this variant. I wouldn’t treat this result as unique to Novavax’s product, at least not until proven to be so.
We’re going to need to keep an eye on this situation. The B.1.351 variant is concerning. We really need to take that seriously.
However, the success of the Novavax vaccine is clear. It even appears to work somewhat against this concerning variant. That gives us another weapon in our arsenal.
Check out the Novavax press release here: https://www.novavax.com/covid-19-coronavirus-vaccine-candidate-updates
Immune mechanisms of long COVID-19
Apoorva Mandavilli of The New York Times reports on the mechanisms that may be behind “long COVID-19,” the worrying and all too common lingering effects of recovery from disease: https://www.nytimes.com/2021/01/28/health/coronavirus-antibodies-immunity.html
She summarizes recent results nicely, describing how these effects are likely caused by “autoantibodies,” antibodies that target the patient’s own proteins. It seems that these are more readily generated during SARS-CoV-2 infection and linger for quite some time after the infection resolves, potentially giving rise to these long term symptoms.
Hopefully the more we learn about this, the better we’ll be able to treat it.
What am I doing to cope with the pandemic? This:
Cooking: Egg rolls, but really focusing on stir-frying
A few weeks ago, I talked about learning to master the stir-fry. One thing that I did in order to do that was get a wok. Since I’m not cooking on some kind of professional burner, I went for a cast iron wok that can retain high heat even if my burner isn’t delivering all the BTUs I might need. It arrived this week, and I’ve started getting into learning with it.
Something I’ve shared before is my work on making egg rolls, like these that I made last night:
What’s really important here isn’t the egg rolls themselves, though, but what’s inside. The filling is a very simple stir-fry of onions, cabbage, and Impossible Beef seasoned with some ginger, five spice, and soy sauce. Using a wok to stir fry this, I was able to get the heat nice and high, and started the onions first, until they started to brown a little while being stirred fast through the hot oil at the bottom of the wok. Then, I added the meat, a little at a time—this is important so as not to drop the temperature of the wok too fast. That will apply in a regular pan too. Also important is to not add large volumes of any wet or water-heavy ingredient, or you’ll start steaming your food instead of stir-frying it. I stir-fried the onions and beef together until I started to get crispy impossible meat sticking to the wok.
One of the nice things about a wok is you can move the ingredients you’ve already cooked out of the center, so they don’t cook as quickly when you add new things. This worked well to my advantage when I started adding the cabbage, which I also added progressively because it’s got a fair amount of water in it.
The nice thing about the high-heat stir-fry approach is you can even caramelize a tough, otherwise rubbery vegetable like cabbage. Cooked fast and hot according to this method, my cabbage started to nicely brown, and mix in well and marry with the flavors in the other ingredients.
Altogether, these made for a nice egg roll filling that held up well when the egg rolls had been fried. I think I’m going to get a bit more adventurous soon, and try stir-frying some things that I don’t have as much experience with.
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See you all next time. Enjoy your weekend!
Always,
JS