COVID Transmissions for 6-11-2021

Vaccination of close contacts can protect children

Jun 11, 2021

Greetings from an undisclosed location in my apartment. Welcome to COVID Transmissions.

It has been 571 days since the first documented human case of COVID-19. U-571 is a film that heavily fictionalizes Allied efforts to capture an Enigma coding device from a Nazi submarine.

The struggle to crack Nazi codes was an international effort that took a lot of collaboration; vaccinating the world against COVID-19 will take a similar effort.

Today we discuss three things: two related to COVID-19 vaccination, and another that expands topics to a different virus that causes tremendous global disruption. It’s good news all around today. Have a nice weekend.

Bolded terms are linked to the running newsletter glossary.

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Now, let’s talk COVID.

Evidence for indirect protection from COVID-19 among unvaccinated people in vaccinated communities

A new paper in Nature demonstrates, through real-world evidence collected in Israel, that people who are not vaccinated can be protected from COVID-19 infection indirectly, if they are surrounded by individuals who are. Paper here: https://www.nature.com/articles/s41591-021-01407-5

Prior to this study, we knew that there were effects of vaccination on reducing infection in vaccinated people, and we also knew that this certainly reduced their chances of transmitting disease. However, it was not as clear that this could translate to indirect protection of unvaccinated people around them (though that’s what everyone would expect). There was also no sense of the magnitude of that protection—how many cases can be prevented among the unvaccinated with each additional vaccinated person? This paper drives at that answer.

This study uses a pretty interesting methodology, one that may be of interest to the parents who read this newsletter. At the time that the data were collected, vaccination was not available in Israel for anyone under the age of 16. They used the population of people under the age of 16 as their unvaccinated cohort.

The rate of COVID-19 in this unvaccinated cohort in various communities was then compared with the rate of vaccinations in older people (ages 16 through 50, chosen because they were considered to be the population who would most frequently interact with the unvaccinated group).

Analyzing the data, the authors find that for every 20 percentage points of population vaccine uptake, the positive test fraction for the unvaccinated group would drop by half. This implies that the unvaccinated, here, were protected by increased rates of vaccination among the rest of the population.

I think it’s worth pointing out that there are limitations to the analysis here. One that jumps out at me, but wasn’t addressed in the paper as far as I saw, is that people under 16 present with COVID-19 less frequently than older individuals, so the effect here may not be strictly the same for all unvaccinated people.

However, I do think that this paper helps to answer some questions I’ve gotten from worried parents about what their children under 12 are supposed to do until vaccines are available to them. The answer here is that they’re supposed to be protected by you getting vaccinated. The more you can surround them with vaccinated people, the better protected they will be. We have clear evidence of this now, which we did not entirely have before.

US to purchase 500 million vaccine doses and donate them to low-income countries

President Biden announced this since last issue: https://www.cnn.com/2021/06/10/politics/joe-biden-vaccine-us-leadership/index.html

500 million doses of Pfizer’s vaccine will protect around 250 million people. This is a drop in the global bucket of around 8 billion people, but it’s definitely progress. This move is likely meant to also bring the US into the game of global vaccine diplomacy more directly. China and Russia have been distributing hundreds of millions of doses of their own vaccines as well, and are thought to be using these distributions to increase their influence around the world. Now the US is counterbalancing that.

This isn’t a political newsletter, so I’ll leave the commentary to the political pundits. I am simply glad to hear that more people around the world will be getting vaccinated. If this turns into an arms race between major powers to vaccinate as many people as possible, well…great! Let’s vaccinate as many people as possible.

Non-COVID: Dengue disease cases can be severely reduced through use of modified mosquitoes

Dengue virus is an incredibly dangerous mosquito-borne pathogen. It causes a short-term debilitating fever with extreme pain, but each subsequent infection carries increased risk of the potentially deadly Dengue hemorrhagic fever, which causes loss of blood and fluid in very unpleasant ways.

It is a scourge of the tropical regions of the world, infecting as many as 500 million people each year. Yes, you read that correctly. For comparison, COVID-19 has infected less than 50 million people that we can document. The scale of these infections causes tremendous human and economic damage around the world every year.

Some years ago, it was discovered that a bacterium, Wolbachia pipitens, could inhibit the ability of mosquitoes to carry Dengue virus. The mosquitoes that most frequently transmit the virus, Aedes aegypti, are not typically colonized with this species of wolbachia. This begged a certain question: if we could colonize A. aegypti with these bacteria, would it prevent transmission of Dengue virus?

A large randomized trial has now answered this question, and to great effect. Release of mosquito eggs colonized with W. pipitens reduced incidence of Dengue locally to those releases by 77% compared with areas where no mosquitoes were released.

This is a really amazing finding, and could change the world with respect to a devastating tropical illness. Read more about it here, at Science magazine news: https://www.sciencemag.org/news/2021/06/mosquitoes-armed-virus-fighting-bacteria-sharply-curb-dengue-infections

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

Pride month!

June is pride month, and I certainly don’t want to let it pass without mention here. Specifically, though, I wanted to talk about some of the great programming that my day job has been running as part of our overall Diversity, Equity, and Inclusion initiatives.

Yesterday, for example, we had a 1-hour webinar from the nonprofit Out & Equal, which specifically tries to make workplaces more welcoming for LGBTQ+ people, about nonbinary gender identities and how to welcome people with nonbinary gender identities in the workplace. It was pretty great.

Part of the reason I mention this is that these initiatives were really born out of the pandemic. Our HR folks decided to use the availability of tools like WebEx and Zoom to create numerous Employee Resource Groups that were available each week to discuss different ways to improve the quality of our workplace for people of all identities. These programs have been extremely well-received, I think partly because they are one of the few ways that we have to connect with our coworkers in the distanced work environment. We’ve turned that need for social connection into a force for better inclusion and diversity, which I really like.

Reader Sam left the following comment:

It seems to me that, in addition to preventing death and hospitalization, we need to figure out how to prevent and manage conditions to like PASC and MIS-C, and soon. It would be nice to know, among other things, whether we're seeing these conditions with the same frequency following vaccine breakthrough infections. The Pfizer EUA review memorandum specifically states, "Additional evaluations will be needed to assess the effect of the vaccine in preventing long-term effects of COVID-19, including data from clinical trials and from the vaccine’s use postauthorization," but I haven't seen anything yet.
Another issue is testing. Potentially we could have treatments that prevent a mild infection from developing into more severe disease -- this is what the antivirals currently being trialed by Merck and Pfizer are hoped to do, I believe. So we need to be able to detect infections ASAP. But we're still stuck with mostly just PCR tests that take days or antigen tests that aren't that accurate, at least on an individual level. What is being done, or can be done, to make more, better, and faster testing widely available?

Sam’s comment and question here are, as ever, astute. Here are my thoughts:

Well, I think you’re right that we need to focus on long-term impacts of COVID. MIS-C, multi-inflammatory syndrome in children, is one condition that I think COVID-19 is actually going to positively impact. While it is not great that children have been affected by it during the pandemic as a result of COVID-19, it has also offered us insight into what may have been causing cases of this syndrome before the pandemic. MIS-C isn’t a new thing. It happened in a small population of children each year already, and nobody was really sure why. Now it is thought that human coronaviruses might be responsible. Other clues have been collected from these cases as well, and I am hoping that this will mark a step forward in addressing this rare condition.
PASC—another name for what’s more commonly called “Long COVID”—is a different matter. I have heard indications that vaccination van resolve symptoms in some patients. It’s not clear why, but Akiko Iwasaki is exploring this over at Yale: https://www.yalemedicine.org/news/vaccines-long-covid
When it comes to testing, I’m not sure that I agree with your characterization of the available testing modalities. PCR and antigen tests, together, are rather impressive. On an individual level, antigen tests are pretty good at identifying symptomatic cases and have a high level of agreement with PCR testing. They’re not perfect, but no test is perfect for anything. The bigger problem with identifying patients for treatment right now, to my mind, is a human one. People are either not using testing, or they are not accepting/being offered appropriate treatment. I have heard many stories about things like this happening. People get sick and they don’t get tested—even though an at-home antigen test is $20-30 and free PCR testing is available with next-day turnaround in many places right now. People who do get tested say they don’t want treatment because their disease isn’t currently serious. Well, I heard one story (through Dr. Daniel Griffin on TWiV) about a married couple where the wife accepted monoclonal cocktail therapy and the husband didn’t because he felt his disease wasn’t too severe. He died, she lived. That’s not the kind of thing that we want to have happening. Dr. Griffin has told many other stories similar to this one as well.
I’m most concerned about these sorts of situations as far as patient identification for treatment. I don’t think testing modalities are going to meaningfully improve beyond where they are now. There aren’t a lot of testing technologies and a large number of them are in use. Each has its limitations but together they will help substantially—provided that the right actions are taken when cases present or are identified.

Where I disagree with Sam here, I think it’s partly a matter of opinion. Maybe I’m being too pessimistic about how much testing can be improved; I don’t know. But from where I sit I think we have tools that can identify patients soon enough to get them good treatment, as long as they get the tests and then get the treatment.

You might have some questions or comments! Send them in. As several folks have figured out, you can also email me if you have a comment that you don’t want to share with the whole group.

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