Air travel study confirms transmission on airplane. Once again kind of an obvious point that at some point this would have occurred. As noted several times before traveling in the airplane itself is one of the safest place as they are required to blend at least 50% fresh air and they typically have HEPA filters. In this case we are looking at Vietnam Airlines – there are no description in the study of filter used and fresh air circulation – but given not a top tier airline I would surmise there is greater probability that they are not the strictest in changing filters and using the best available. https://wwwnc.cdc.gov/eid/article/26/11/20-3299_article

“To assess the role of in-flight transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), we investigated a cluster of cases among passengers on a 10-hour commercial flight. Affected persons were passengers, crew, and their close contacts. We traced 217 passengers and crew to their final destinations and interviewed, tested, and quarantined them. Among the 16 persons in whom SARS-CoV-2 infection was detected, 12 (75%) were passengers seated in business class along with the only symptomatic person (attack rate 62%). Seating proximity was strongly associated with increased infection risk (risk ratio 7.3, 95% CI 1.2–46.2). We found no strong evidence supporting alternative transmission scenarios.”

“Flight VN54 departed London at 11:10 am local time on March 1, 2020, and arrived in Hanoi at 5:20 am local time on March 2; the nonstop flight lasted about 10 hours. A total of 16 crew members and 201 passengers were on board. The 274 seats on the airplane were divided into business class (28 seats), premium economy class (35 seats), and economy class (211 seats); there were 4 toilets for business and premium economy classes and 5 for economy. The business class was exclusively reserved and separated from the premium economy and economy classes by a service/toilet area (Figure 1). Of the 201 passengers, 21 occupied business (75% seats occupied), 35 premium economy (100%), and 145 economy (67%) seats (Figure 1). Two meals were served, and flight attendants worked in 2 teams, 1 for the business and premium economy sections and 1 for the economy section.”

“By March 10, all 16 (100%) of the flight crew and 168 (84%) of the passengers who remained in Vietnam had been traced; 33 (16%) passengers had already transited to other countries. We were able to quarantine, interview, and collect swab specimens for PCR testing from all passengers and crew members who remained in Vietnam. Passengers and crew had traveled on to 15 provinces in Vietnam, ranging from Lao Cai and Cao Bang in the north to Kien Giang in the south.

Through these efforts, we identified an additional 15 PCR-confirmed COVID-19 cases, 14 among passengers and 1 among crew members, resulting in a total of 16 confirmed flight-associated cases.”

“The most likely route of transmission during the flight is aerosol or droplet transmission from case 1, particularly for persons seated in business class (23). Contact with case 1 might also have occurred outside the airplane at the airport, in particular among business class passengers in the predeparture lounge area or during boarding. Although Vietnam Airlines keeps business class passengers separated from economy class passengers during most procedures before and during the flight, contact with the 2 economy class cases might have occurred after arrival during immigration or at baggage claim. We also note that 2 passengers, in the seats between the 2 cases in economy class, were lost to follow-up. Whether either of these passengers could represent a separate index case in economy class is unknown.

The role of fomites and on-board surfaces such as tray tables and surfaces in toilets remains unknown. For example, airline crew often use business class toilets while on board, which might explain the case among the crew serving in economy class, for whom no other potential source of infection could be established. Of note, the temporal sequence of symptom onset among cases in economy class and the crew member serving in economy class also allows for the possibility of a second in-flight transmission event, independent of the cluster in economy class”

“First, thermal imaging and self-declaration of symptoms have clear limitations, as demonstrated by case 1, who boarded the flight with symptoms and did not declare them before or after the flight. Second, long flights not only can lead to importation of COVID-19 cases but also can provide conditions for superspreader events. It has been hypothesized that a combination of environmental factors on airplanes (humidity, temperature, air flow) can prolong the presence of SARS-CoV-2 in flight cabins (27). No evidence indicated that the regular air conditioning and exchange system on flight VN54 were malfunctioning”

“The latest guidance from the international air travel industry classifies the in-flight transmission risk as very low (34) and recommends only the use of face masks without additional measures to increase physical distance on board, such as blocking the middle seats (7,35). Our findings challenge these recommendations. Transmission on flight VN54 was clustered in business class, where seats are already more widely spaced than in economy class, and infection spread much further than the existing 2-row (36) or 2 meters (37) rule recommended for COVID-19 prevention on airplanes and other public transport would have captured. Similar conclusions were reached for SARS-CoV superspreader events on a flight in 2003, in which a high risk for infection was observed for passengers seated farther than 3 rows from the index case (4). This finding also concurs with transmission patterns observed for influenza virus (38) and is generally in line with the mounting evidence that airborne transmission of SARS-CoV-2 is a major yet underrecognized transmission route (39,40).”

“We conclude that the risk for on-board transmission of SARS-CoV-2 during long flights is real and has the potential to cause COVID-19 clusters of substantial size, even in business class–like settings with spacious seating arrangements well beyond the established distance used to define close contact on airplanes. As long as COVID-19 presents a global pandemic threat in the absence of a good point-of-care test, better on-board infection prevention measures and arrival screening procedures are needed to make flying safe.”

Their conclusions are very dire. However I think its people looking for a dramatic conclusion to get attention – if we look at the data to actually see what actionable item we can take away to make things better we can see there is potential and conclusions that there is something that makes air travel safer than the office or home gathering. I am certain if you put the restaurant study for 10 hours the spread would have been much more significant. At the same time if you relate it to another airline study which ACTUALLY wore N95 mask – once again prove the obvious that mask help – there we had asymptomatic carriers but hardly any spread. https://wwwnc.cdc.gov/eid/article/26/11/20-3353-f1

Why are not people investigating the differences in fresh air circulation of the various airplane to find the root solution to make areas safer – the HEPA filter used – fresh air circulation setting? Munich to Shanghai – no spread – https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30314-5/fulltext

“Extensive contact tracing involved the international flights from Munich to Shanghai (patient 0 on Jan 22, 2020) and from Munich to Tenerife (patient 12 on Jan 28, 2020). As of May 2, no further cases have been identified among flight passengers or other (personal) contacts.”

Too easy to get caught up in getting clicks and attention using fear vs trying to find solutions to the problem seems to by pervasive.

Tcells we talked about this several times already – https://www.dailymail.co.uk/health/article-8749589/Up-50-people-immune-cells-fight-coronavirus.html

“A study of donated blood in the US found that half of samples had immune T cells that reacted to SARS-CoV-2

Similarly high rates were found in smaller studies of blood from people in the UK, Singapore, Germany and the Netherlands

T cells developed to fight other coronaviruses might be ‘cross reactive’ with the new virus that causes COVID-19”

“COVID-19 is thought to be so deadly in part because it’s an entirely new virus to which humans have no natural immunity.

And while that is clearly the case for many people, British Medical Journal associate editor Dr Peter Dosh wrote on Thursday that the evidence is beginning to suggest that some people may possess some protection against the virus.”

“scientists are starting to look more carefully at T cells, which, like antibodies, are part of the adaptive immune system and learn to identify and combat specific pathogens.

“Although SARS-CoV-2 itself is new, it belongs a family of many related coronaviruses.

Scientists think that some people may have developed T cells for other coronaviruses that are ‘cross-reactive’ with SARS-CoV-2 because they are sufficiently similar.

If that’s the case, the world may be closer to herd immunity to the deadly infection than we think – but much research remains to be done before we can know if that is the case. “

My suspicion/hypothesis is the coronavirus being akin to the common cold then those who have gotten sick with colds often when young likely built up a good immune system. Those living in ultraclean environment e.g. hand sanitizer world (US and UK) likely did not get that opportunity and are essentially paying the price for that.

VERY concern about this current generation of kids who have been swamped with hand sanitizer use and massive cleaning – we could be doing a great disservice to them for the future. This is the Yin/Yang of nature – the Buddhist measure of suffering requirement – eliminate the common cold will only build up the suffering for later.

This is why cold water therapy and other likes work. You continually challenge your body and it meets the challenge. If you baby the body it will not be prepared for a real attack.

Parents taking pride of not having their child ever getting sick – well that’s really probably a big disservice to them in the future.

I think we are probably officially heading into the lull season for covid – US under 1K again. The weather in the US is looking like open Windows for most of the US now.

Florida leads the US at 139

Miami-Dade leads the US counties at 50

Fatality rate in Harris county now closer to 1% for the last week

I don’t like to look at aggregations too much but it is interesting to note confirmations changes worldwide have grown 3+X since April (70K to 260K per day) yet death has stayed steady and actually is down from April….worldwide death 7 day moving average 5K per day…April as high as 7K per day.