COVID Transmissions for 5-31-2022
Vaccines for young children; air travel safety
Greetings from an undisclosed location in my apartment. Welcome to COVID Transmissions.
It has been 906 days since the first documented human case of COVID-19. In 906, famed Chinese landscape painter Guan Tong was born. In today’s world, we take the ability to produce lifelike images of the natural world for granted, but when Guan Tong lived, this was far from commonplace. He developed a talent for doing it, an important milestone in the history of art.
We’ll talk about a couple of technologies in the COVID-19 context today, too—early childhood vaccination and the amazing, but potentially virologically dangerous, technology of air travel.
Despite my best efforts, work travel interfered with my writing schedule, and I come to you with my regrets for the unexpected skip week. I’m back, and I’ll be trying to write you more frequently going forward. I’m hoping that either this week, or early next, I’ll be able to put some words down about monkeypox, the other viral disease that has been making headlines lately.
Bolded terms are linked to the running newsletter glossary.
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Now, let’s talk COVID.
Pfizer-BioNTech data on vaccination in children from 6 months to 5 years of age
Pfizer and BioNTech announced recently that they have successful results for a 3-dose regimen of their vaccine in the youngest children investigated, ranging in age from 6 months old to 5 years: https://www.washingtonpost.com/health/2022/05/23/children-coronavirus-vaccine-pfizer-data/
They report their findings in a press release, emphasizing an actual vaccine efficacy (VE) against symptomatic disease rather than a biochemical/immunological endpoint: https://www.pfizer.com/news/press-release/press-release-detail/pfizer-biontech-covid-19-vaccine-demonstrates-strong-immune
Here, they indicate an 80.3% VE against symptomatic disease in the youngest children. That’s a nice number to hear, but I need to emphasize that the press release just isn’t enough, and even that press release emphasizes that these are preliminary analyses. The study hasn’t reached its prespecified statistical analysis points for everything yet, and so we need to wait a bit. I want to see the full FDA filing, and I understand that the time will come when I do get to see it—since it will be public. When that happens, you can expect it to be covered here.
However, this does leave me feeling optimistic. Moderna has already reported success in youngest children, and now with Pfizer-BioNTech reporting the same, we have two strong candidates for childhood vaccination. This is exciting, because it would close a major gap in COVID-19 vaccination and move us closer to being able to protect everyone who wants it. It’s also exciting, though, because children grow into adults, and the ability to vaccinate everyone in childhood going forward will be an essential strategy on what is bound to be at least a decades-long fight against COVID-19.
As I’ve written many times, the evidence support that the best way to encounter SARS-CoV-2 antigens for the first time is from a vaccine rather than from live virus. No one should count on avoiding this virus forever, so it’s a choice between getting protected by a vaccine or taking the risks of getting sick. Without a vaccine for the youngest children, they’re being forced into the latter, and that is terrible. If a vaccine can be approved, we will have a good chance of giving everyone the protection they need for their full life cycle. That’s extremely important, and after a long time of worrying, I’m now hopeful that we can see success here.
Airline infrastructure problems and my stance on masks in transport
There is a story that has been going through a bit of a smoldering build in the background of the COVID-19 pandemic: the impact of the disease on airlines. Airplanes are a hot topic in infectious disease, particularly when it comes to respiratory illnesses—but also in the realm of other types of disease.
On the one hand, aircraft are very good at moving people, including people who are sick from or incubating infection, across large distances. Before air travel, a disease had to have pretty specific features in order to cross, say, the Atlantic Ocean. If the entire course from infection to the end of the contagious period was shorter than a typical sea voyage, then it needed to encounter new susceptible hosts during the journey.
Now it takes 5 hours to cross the Atlantic, which makes for very different dynamics. The Omicron variant of SARS-CoV-2, which has an infectious window on the order of days, spread from somewhere on the African continent to the UK in less than a couple of weeks (most likely). Unfortunately I can’t compare how fast this is with an example from before airplanes existed, because modern genomics is younger than the airplane, but I feel comfortable betting that it took a longer period of time, and a greater degree of unlucky circumstance, for viral illnesses to spread so rapidly before air travel.
On the other hand, aircraft are very sophisticated pieces of machinery and a lot of thought actually goes into their air-handling systems for internal cabin climate control. Aircraft have advanced filtration systems that are meant to pull pathogens (and other potentially dangerous particulates) out of the circulating air. When the COVID-19 pandemic began, a lot of work was put into determining how well (or not well) SARS-CoV-2 can be transmitted on planes. The International Air Transport Association (IATA), an organization which exists to promote and support the air travel industry, maintains that the risk of transmission of COVID-19 aboard aircraft is low. See this on their website: https://www.iata.org/en/youandiata/travelers/health/low-risk-transmission/
That website makes some fairly convincing arguments, but I think we have to stick through this to the end here. One thing I want to call out is that website itself does cite some more independent research, including this: https://cdn1.sph.harvard.edu/wp-content/uploads/sites/2443/2020/10/Phase-One-Report-Highlights-1.pdf
That link is a report prepared by the faculty of the Chan School of Public Health at Harvard. The report does say that with mitigation measures, the risk of COVID-19 contagion aboard aircraft (gate-to-gate, specifically), is “low.” However, those mitigation measures include the use of face coverings. We’ll come back to that.
A somewhat more balanced picture, and I think a more approachable one, is offered by this interactive piece from The New York Times: https://www.nytimes.com/interactive/2021/04/17/travel/flying-plane-covid-19-safety.html
As you can see in that video, while air exchange within an aircraft is robust, it is possible for there to be pockets of air that are contaminated for periods of time. There were documented situations of transmission during flights as far back as 2020, which were collected into this handy publication: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7543400/
If you go through the table of events in that paper, it should leave you convinced that the statement that transmission risk is “low” does not mean it is anything resembling “impossible.” And, as the NYT piece emphasizes, transmission on the plane isn’t the only venue for transmission during travel—there’s the airport, the jet bridge, the boarding process (when the aircraft air system isn’t always running), etc.
This was the situation a year or more ago, when we were talking about Wuhan- and alpha-variant SARS-CoV-2. Today, we are talking about Omicron BA.4 and BA.5 variant viruses that are possibly many times as contagious as what was circulating when that NYT piece first ran.
In fact, despite the statement on their website throughout much of the pandemic that COVID-19 transmission risk is “low” on aircraft, in December 2021 an IATA spokesperson told Bloomberg news that with Omicron, it is now two to three times higher than before: https://www.forbes.com/sites/siladityaray/2021/12/22/airplane-passengers-at-least-twice-as-likely-to-catch-covid-19-because-of-omicron-airline-trade-body-says/?sh=5a7e5ba536b8
It’s curious to me, then, that there has been a nearly industry-wide push to drop mask mandates on aircraft in 2022. When the UK dropped mask requirements for aircraft, I thought they were making a big mistake. As it turns out, they were. Shortly after mask requirements were dropped, we started to hear news of flight cancellations because airlines were no longer able to find crew that were healthy enough to fly. There are dozens, if not hundreds, of news stories about this, but here’s just one from April 2022 suggesting that disruptions could last for months: https://abcnews.go.com/International/wireStory/uk-airport-warns-covid-related-delays-months-83955318
This has turned out not to be unique to the UK. Following the removal of the US mask mandate, there were also flight cancellations due to crew illness. As of this writing, news outlets are reporting thousands of flight cancellations over the Memorial Day weekend here. This article reports 7,000 cancellations: https://www.cbsnews.com/news/memorial-day-weekend-travel-flight-cancellations/
Meanwhile, Delta airlines (which led the weekend for cancellations), has announced that they will be cutting 100 flights altogether in the summer of 2022. When I say “flights” in this paragraph, I don’t mean individual journeys. I mean regularly scheduled routes; they’re going to be off the schedule now because Delta doesn’t feel they can guarantee the flights will take place to their standards, including being able to get enough crew due to COVID-19: https://www.cnn.com/travel/article/delta-air-lines-cuts-summer-schedule/index.html
I’ll note that some months ago, the CEO of Delta called for an end to mask mandates on transportation. Now it appears that position, which has become policy, is directly harming airlines’ ability to operate.
This situation was predictable, and I think it underscores how we need to be thinking about COVID-19 in a world where we cannot rely on everyone to get on board and protect themselves. Many months ago I might have said we can locally eliminate or even just control COVID-19; now I think that we have gotten into a situation where the best we can do is prevent COVID-19 from controlling us.
I think it’s particularly important, then, for us to think about the settings where the spread of COVID-19 has the greatest likelihood of causing massive disruptions. Transportation is a setting like that. Keeping crews healthy is essential to keeping the trains—or whatever—running. Since so many things rely on travel and transport, I think it’s pretty important that we keep COVID-19 under control at least among the people who work on these vital activities.
I’m not holding out for a world where mask mandates that have been lifted will be restored; this has become a political issue and I am not a politician. Instead I have been focusing on ways that I can provide practical insights on what the individuals who read my writing can do to maximize their protection.
On the other hand, I do think transportation is a place where we would do well to restore a mandate, for very immediate and practical reasons. Transportation safety prevents disruption to global systems of transportation, and masks need to be a part of that.
Part of science is identifying and correcting errors. If you find a mistake, please tell me about it.
Though I can’t correct the emailed version after it has been sent, I do update the online post of the newsletter every time a mistake is brought to my attention.
No corrections since last issue.
What am I doing to cope with the pandemic? This:
Celebrating a birthday
My birthday was yesterday. I spent most of it outside in New York City, where the weather was lovely. I spent some of it writing these words for you.
I’m looking forward to a year where this newsletter falls more into a genre of interesting science writing and less into a genre of essential information to stay safe. I hope that’s what we get.
I’m a little behind on newsletter tasks, so I’m going to skip a recap of last issue’s comments today. I did see some interesting things come through, though, so go have a look at what’s there.
You might have some questions or comments! Join the conversation, and what you say will impact what I talk about in the next issue. You can also email me if you have a comment that you don’t want to share with the whole group, or if you are unable to comment due to a paywall.
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Please know that I deeply appreciate having you as readers, and I’m very glad that if we must be on this pandemic journey, at least we’re on it together.
Always,
JS
One thing to keep in mind about that 80.3% figure: it refers to VE across both cohorts -- 6 months to 2 years and 2-4 years. However, the immunobridging goal was met in the 6 month - 2 year cohort even with two doses; it failed to be met only for kids 2-4 years old. Thus, it's possible the VE is substantially lower for the 2-4 year old age group.
There are non-nefarious reasons for presenting the data this way: some of the kids likely aged out of the younger cohort during trial. Still, I've already heard of pediatricians planning to order only the Pfizer vaccine due to its "higher efficacy." That's unfortunate, and not only because it relies on a misreading of the data (insofar as we can even call a press release data). The two months kids wait for their third shot are two months in which they can be infected. Also, the immune response elicited by Moderna's vaccine may be a bit more durable, based on what we see in adults. Thus, it's unclear how much more protective opting for Pfizer over Moderna would actually be in real-world conditions.
Relatedly, I'm sure you saw Moderna's announcement today of promising preliminary data on its bivalent vaccine targeting Omicron. Assuming regulators decide an updated vaccine is required, I'd like to know what the plan is for getting it to kids. I sure hope the question is addressed at the VRBPAC meeting later this month. We can't wait 18 months again.
This is a great post, and thanks for the timely deep dive on the safety of airplanes and air travel. I'm going to review the NYT article, and probably skip travel this month that I had hoped to do. Europe is a variant mess, and the guy sitting next to me shoulder to shoulder on an overcrowded flight can now breathe directly into me without a mask on. Such a sick culture.