Thread by @DrEricDing

An airplane janitor staff in Auckland🇳🇿 airport, who cleans planes “that flew internationally”—is positive for #COVID19 in weekly testing. 2x-Pfizer vaccinated, family neg, the cleaner’s job is “non-public facing”. Plane aerosol transmission?

(@WicMar ht)
health.govt.nz/news-media/med…

2) NZ health authorities add “The person has been fully vaccinated—received two doses of Pfizer/BioNTech vaccine early in the vaccination campaign—in February and March. We know the Pfizer vaccine is highly effective, but at 95% effectiveness a small number may not be protected.”

3) “Breakthrough infections happen with all vaccines. This shows us how important it is that as many New Zealanders as possible take up the offer to receive vaccine when offered it and are protected. The more people that are vaccinated, the more protected we will all be.”

4) “The PCR test from this case has been sent for whole genome sequencing – the Ministry expects to be able to provide an update on this result tomorrow. The results of the whole genome sequencing will help provide information on how the person became infected with COVID-19.”

5) I like this part—“A final note of thanks to this person – they, like many others at our border, have worked in an environment during this pandemic that has exposed them to the virus that we have collectively worked so hard to keep out.”

6) “This person has done the right things – they have been regularly tested, and we know they have been using NZ COVID Tracer app, with Bluetooth turned on. People working at our border deserve our thanks and appreciation, and our thoughts are with this person as they recover”

7) We know that 72-hour predeparture testing is not enough to capture all cases before boarding flight. And after planes land, we know the engines of many planes turn off, and air filtration system is sometimes not operated or at low levels when passengers disembark. Reality.

8) NZ “Ministry of Health believes there is a clear link to the border as the source of the infection”, adding the staffer cleaned “planes that have flown internationally from countries where COVID-19 is widespread.”

9) “Their work at Auckland Airport is their sole employment, and their role is non-public facing.
Additional pop up testing has been set up at Auckland Airport. Locations of interest where people may have been at the same time as the case will be shared as they are available.”

10) “This case is a reminder that everyone in New Zealand should be using the NZ COVID Tracer app – if you have scanned in at a location with someone who has COVID-19 you will be sent a notification through the app which is the quickest and easiest way to protect your whanau.”

11) I think Bluetooth contact tracing app is useful for close distance contact, but I don’t even think close contact is even needed when aerosols in a closed environment like the airplane or it’s lavatory can hold aerosol particles for hours at a time if air filtration is off.

12) How is aerosol different from large droplets? aerosol study indicates that coronavirus is persistent and stable for many hours. Typical air exchange every 20 min to 4 hrs, depending on ventilation. Longer if air system is off. #COVID19

13) VENTILATION is key. Both ventilation and masks needed to reduce risk indoors. But most buildings not ventilated well enough. Airplanes usually good filtration but not when airplane is on the ground after passengers disembarked.

14) Also good time to remind people that vaccines WORK, but for mild/asymptomatic transmission, they are not always perfect, as NZ ministry of health noted. here is a table of many vaccines and asymptomatic efficacy.

https://twitter.com/DrEricDing/status/1377861074293260288?s=20

15) There is a HUGE reason we need border quarantines. Airplane transmission and hotel transmission can happen and 72-hour-testing can miss cases. See thread 🧵

https://twitter.com/drericding/status/1384077181664432131

16) And hotels for quarantines must take extra precaution against airborne transmission. We know cross hotels room transmission can occur if not careful.

https://twitter.com/DrEricDing/status/1383251471760707586

17) Let this sink in — between April 1-17, Canada has recorded airplane arrival cases from Delhi, India on flights every day, usually 2-3 flights per day, sometimes all 4. Border testing and border quarantines may need to be added for certain flights from hotspot areas.

https://twitter.com/bryanpassifiume/status/1384324349486780421