Read on Twitter
THREAD: CoV-2 Transmission Studies. Will update.
FYI
@afemafrica @ErmiasMd @CatchTheBaby @MohamedBailorB8 @AfricaCDC @WHOAFRO @komba_albert @erwinlo @marcyambayamba
@iceman_ex @Dr_FarrisD @Alissa_Moen @lisanoguchi @roeckler @proneprincess @ChuxNesta_Nnaji @19criticalcare
FYI
@afemafrica @ErmiasMd @CatchTheBaby @MohamedBailorB8 @AfricaCDC @WHOAFRO @komba_albert @erwinlo @marcyambayamba
@iceman_ex @Dr_FarrisD @Alissa_Moen @lisanoguchi @roeckler @proneprincess @ChuxNesta_Nnaji @19criticalcare
Droplets can travel 7-8 metres with sneezing - paper published JAM 26th March 2020 raised concern about advice that droplets can travel 6 feet (2 metres) based on study showing sneezing can create clouds that travel 23 to 27 feet (7-8 m) https://jamanetwork.com/journals/jama/fullarticle/2763852
Highest concentration of aerosols in air samples found in a donning doffing room in a hospital in China (RNA, not cultured) https://www.nejm.org/doi/full/10.1056/NEJMc2004973
Aerosols in air samples from various places in the hospital (unsuccessful culture) https://www.medrxiv.org/content/10.1101/2020.03.23.20039446v2
Previously a MERS study successfully cultured virus from air samples https://academic.oup.com/cid/article/63/3/363/2595016
A study published in 2020 demonstrated/concluded aerosol transmission of influenza in schools (influenza is 80-120nm SARS-SoV-2 60-140nm) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7002614/ .
A number of studies have demonstrated aerosolisation of influenza with exhalation, coughing and sneezing e.g. https://www.ncbi.nlm.nih.gov/pubmed/26991074
Two SARS (2003) studies suggested aerosol transmission in settings where "aerosol generating procedures" do not take place (an aircraft...) 1/2 https://www.nejm.org/doi/full/10.1056/NEJMoa031349
... and airborne/aerosol transmission of SARS (2003) in a housing complex. 2/2 https://www.nejm.org/doi/full/10.1056/NEJMoa032867
A study is currently being conducted in Sweden to evaluated aerosolisation of SARS-CoV-2 with normal breathing.
Evidence of asymptomatic transmission (not definitive) 1/ https://jamanetwork.com/journals/jama/fullarticle/2762028
Case of asymptomatic transmission in Germany https://www.nejm.org/doi/full/10.1056/NEJMc2001468
Transmission after clinical recovery/symptoms resolve. Study showed viral shedding ? up to 12 days after symptoms resolved and after seroconversion) https://www.medrxiv.org/content/10.1101/2020.03.05.20030502v1.full.pdf
Single studies that found NOT a mode of transmission. Sexual https://www.medrxiv.org/content/10.1101/2020.02.26.20028225v2
Intrauterine ( https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)30360-3/fulltext)
Breastmilk https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciaa200/5771323
Urine https://jamanetwork.com/journals/jama/fullarticle/2762997
Intrauterine ( https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)30360-3/fulltext)
Breastmilk https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciaa200/5771323
Urine https://jamanetwork.com/journals/jama/fullarticle/2762997
Faecal oral potential "Duration time of positive stool ranged from 1 to 12 days. Furthermore, 17 (23.29%)
patients remained positive in stool after showing negative in respiratory samples" https://www.gastrojournal.org/article/S0016-5085(20)30282-1/pdf
patients remained positive in stool after showing negative in respiratory samples" https://www.gastrojournal.org/article/S0016-5085(20)30282-1/pdf
Re fomites, SARS-CoV-2 survives on surfaces up to 9 days (varies depending on material, plastics >) https://www.journalofhospitalinfection.com/article/S0195-6701(20)30046-3/fulltext
Update intrauterine "A neonate born to a mother with COVID-19 had elevated antibody levels ... elevated IgM antibody level suggests that the neonate was infected in utero. IgM antibodies are not transferred to the fetus via the placenta." https://jamanetwork.com/journals/jama/fullarticle/2763853
Another study suggesting vertical transmission https://jamanetwork.com/journals/jamapediatrics/fullarticle/2763787
"The possibility of faecalâoral ... has implications, especially in areas with poor sanitation. ..Future research... should include environmental studies to determine whether the virus remains viable in conditions that would favour such transmission." https://www.thelancet.com/journals/langas/article/PIIS2468-1253(20)30048-0/fulltext
"patterns of viral shedding in 94 laboratory-confirmed COVID-19 patients... Our modeling analysis suggests that viral shedding may begin 2-3 days before showing first
symptoms. After symptom onset, viral loads decreased monotonically" https://www.medrxiv.org/content/10.1101/2020.03.15.20036707v2.full.pdf
symptoms. After symptom onset, viral loads decreased monotonically" https://www.medrxiv.org/content/10.1101/2020.03.15.20036707v2.full.pdf
Response to vertical transmission studies, noted poor sensitivity of IgM alone as indicator of intrauterine transmission. https://jamanetwork.com/journals/jama/fullarticle/2763851
Experimental study inoculated animals "SARS-CoV-2 replicates poorly in dogs, pigs, chickens, and ducks, but efficiently in ferrets and cats... transmits in cats via respiratory droplets." NB non-science readers this doesn't show human <-> cat transmission. https://www.biorxiv.org/content/10.1101/2020.03.30.015347v1.full.pdf
Report to CDC "Investigation of all 243 cases of COVID-19 reported in Singapore during January 23âMarch 16 identified seven clusters of cases in which presymptomatic transmission is the most likely explanation for the occurrence of secondary cases." https://twitter.com/UCI_IDScience/status/1245397241856028674?s=20
A number of cats whose owners have had COVID-19 in Belgium and Hong Kong have tested positive (news report). Also news report today of a Tiger in the New York zoo positive with respiratory symptoms. No study has investigated cat to human transmission yet. https://www.reuters.com/article/us-health-coronavirus-hongkong-pets/pet-cat-tests-positive-for-coronavirus-in-hong-kong-idUSKBN21J3RI
[artificially generated] Aerosol-spread during chest compressions in a cadaver model. "The use of a surgical mask deflected the spread. Inserting a laryngeal tube connected to an airway filter lead to a remarkable reduction of aerosol-spread." https://www.medrxiv.org/content/10.1101/2020.03.31.20049197v1
"Speaking may be a primary mode of transmission of SARS-CoV-2... We found that saying the words 'Stay Healthy' generates thousands of droplets that are otherwise invisible to the naked eye. A damp homemade cloth face mask... reduced droplet excretion" https://www.medrxiv.org/content/10.1101/2020.04.02.20051177v1
(Dr Erwin @erwinloh I tagged you in this thread initially it appears using the wrong twitter handle)
