You can't get far in a COVID discussion without someone claiming the vaccines don't "stop" transmission. So for reference, here's a non-exhaustive list of published studies & preprints that show being vaccinated against COVID reduces the likelihood of COVID transmission. 🧵
"Effect of Vaccination on Transmission of SARS-CoV-2" by Shah et al
nejm.org/doi/full/10.10…
"Vaccine effectiveness against SARS-CoV-2 transmission to household contacts during dominance of Delta variant (B.1.617.2), August-September 2021, the Netherlands" preprint by de Gier et al
medrxiv.org/content/10.110…
"The impact of SARS-CoV-2 vaccination on Alpha & Delta variant transmission" by Eyre et al
medrxiv.org/content/10.110…
"Virological characteristics of SARS-CoV-2 vaccine breakthrough infections in health 2 care workers" preprint by Shamier et al
medrxiv.org/content/10.110…
"Third doses of COVID-19 vaccines reduce infection and transmission of SARS-CoV-2 and could prevent future surges in some populations" by Gardner et al
medrxiv.org/content/10.110…
"Virological and serological kinetics of SARS-CoV-2 Delta variant vaccine breakthrough infections: a multi-center cohort study" by Chia et al medrxiv.org/content/10.110…
"Community transmission and viral load kinetics of the SARS-CoV-2 delta (B.1.617.2) variant in vaccinated and unvaccinated individuals in the UK: a prospective, longitudinal, cohort study" by Singanayagam et al
sciencedirect.com/science/articl…
"SARS-CoV-2 Omicron VOC Transmission in Danish Households" preprint by Lyngse et al medrxiv.org/con.../10.1101…
There are certainly others, and if you know one I've missed, feel free to drop a link. The upshot is that although COVID vaccines don't eliminate the possibility of transmission, the evidence supports the logic that they reduce the chance of transmission to others.
I meant to mention in each tweet whether it is a preprint, so I apologize for missing that. I am also interested in whether and when each preprint ends up published, so if anyone has info on any of these papers, please let me know.
I’m going to add some more studies given to me by helpful readers, but let me clear a couple of things up first.
My link for "SARS-CoV-2 Omicron VOC Transmission in Danish Households" preprint by Lyngse et al is broken. Here is the fixed link. medrxiv.org/content/10.110…
This appears to be the updated, published version of that study, which focuses on Omicron.
nature.com/articles/s4146…
As Omicron and its subvariants, are more recent than other variants, there are going to be fewer studies on transmission for them. And none that I know of yet on the bivalent booster with regards to transmission.
This is a list of transmission studies across the variants, as the argument that they don’t affect transmission has been happening since the first variant. But the data we have (pre bivalent booster) indicate vaccination decreases Omicron transmission as well (see Lyngse et al).
I’m not trying at all to argue vaccines mean other mitigation efforts aren’t needed. I made this list to address the myth that vaccines don’t affect transmission, therefore there's no rationale to require them for work/schools/healthcare/etc or to get them to help protect others.
Another Omicron study that was in my bookmarks but I forgot to include. And I'm double checking links now!
"Infectiousness of SARS-CoV-2 breakthrough infections and reinfections during the Omicron wave" preprint by Tan et al
medrxiv.org/content/10.110…
“Vaccination with BNT162b2 reduces transmission of SARS-CoV-2 to household contacts in Israel” by Prunas et al
medrxiv.org/content/10.110…
“Indirect protection of children from SARS-CoV-2 infection through parental vaccination” by Hayek et al
science.org/doi/10.1126/sc…
“Longitudinal analysis of SARS-CoV-2 vaccine breakthrough infections reveal limited infectious virus shedding and restricted tissue distribution” by Ke et al medrxiv.org/content/10.110…
“Impact of population mixing between vaccinated and unvaccinated subpopulations on infectious disease dynamics: implications for SARS-CoV-2 transmission” by Fisman et al
cmaj.ca/content/194/16…
"Transmission and Infectious SARS-CoV-2 Shedding Kinetics in Vaccinated and Unvaccinated Individuals" by Jung et al
jamanetwork.com/journals/jaman…
And a couple more, relevant to Omicron:
"Association of mRNA Vaccination With Clinical and Virologic Features of COVID-19 Among US Essential and Frontline Workers" by Fowlkes et al
jamanetwork.com/journals/jama/…
Finally (for now) "Infectious viral load in unvaccinated and vaccinated individuals infected with ancestral, Delta or Omicron SARS-CoV-2" by Puhach et al. Get boosted!
nature.com/articles/s4159…
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