Nathan Lo Profile picture
Jan 2 15 tweets 18 min read
🧵1/N How do vaccines and/or natural infection change infectiousness of #COVID19 during #Omicron? Our new article published in @NatureMedicine measures #COVID19 infectiousness, and finds reductions from both vaccine and natural infection. nature.com/articles/s4159…
2/N We use detailed epidemiologic data from SARS-CoV-2 surveillance within the California prison system to study #COVID19 transmission. Our goal was to translate these findings into policy to improve health for this vulnerable incarcerated population that remains at high risk.
3/N We performed a close contact study of index cases with #COVID19 to measure their infectiousness, by comparing their vaccine and natural infection history. We followed their close contact (residents who shared a room) over time to estimate secondary attack rates. Design here:
4/N In our main analysis, we found that any #COVID19 vaccine reduced infectiousness by 22% (6–36%) and prior infection reduced infectiousness by 23% (3–39%). Hybrid immunity reduced infectiousness by 40% (20–55%).
5/N The raw numbers: Vaccinated residents with breakthrough infections were significantly less likely to transmit infection to others: 28% versus 36% for those who were unvaccinated.
6/N Key insight #1: The least infectious #COVID19 cases were those who had been recently vaccinated and/or had booster doses.
7/N Key insight #2: For persons previously infected, we found additional benefit of vaccination to further reduce infectiousness in subsequent #COVID19 infections.
8/N Policy take away #1: COVID-19 risk remains high in the incarcerated population and vaccines are not enough to stop transmission
9/N Policy take away #2: Based on our finding that people are least infectious within two months of vaccination, large timed vaccination campaigns may have a role to reduce transmission in surges. Future work is needed.
10/N Thank you to the team who made this work possible. Lead author Sophia Tan, upcoming super-🌟 in ID public health research. Dr. @realdavIDsears and Dr. @kwantada who made this collaboration possible. Appreciate support from California Correctional Health Care Services.
11/N Prior @Nature coverage of our study here: nature.com/articles/d4158…
12/N @UCSF press release here: ucsf.edu/news/2022/12/4…

• • •

Missing some Tweet in this thread? You can try to force a refresh
 

Keep Current with Nathan Lo

Nathan Lo Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!

PDF

Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @NathanLo3579

Mar 22, 2021
1/N Our new study published in @TheLancetInfDis on #COVID19 testing strategies for safer airline travel. Getting tested before and after air travel can prevent the spread of #COVID19 and make flying safer. Collab led by the singular Dr. @mathewkiang. thelancet.com/journals/lanin…
2/N What is the best #COVID19 testing strategy when traveling? We find pre-travel testing (PCR 3 days before travel or rapid antigen test on travel day) reduces risk of being infectious on airplane by ~88%, but post-travel quarantine/testing needed to reduce risk of importation.
3/N We simulated 100,000 travelers and used published data on the transmission of SARS-CoV-2 to estimate our study outcomes: i) total number of infectious days (public health perspective); ii) proportion of infectious travelers detected on day of travel (individual perspective).
Read 14 tweets
Dec 11, 2020
1/N *Our new pre-print study now posted* What is the best #COVID19 testing strategy when traveling? We find pre-travel testing reduces risk of being infectious on airplane by ~87%, but post-travel quarantine/testing needed to reduce risk of importation. medrxiv.org/content/10.110…
2/N With the holidays, travel is likely to skyrocket. Our analysis finds that no testing strategy can eliminate risk of infection during travel or risk of bringing infection to a new place. Therefore, traveling should only be done when essential, esp given number of #COVID cases!
3/N We simulated 100,000 travelers and used published data on the transmission of SARS-CoV-2 to estimate our study outcomes: i) total number of infectious days (public health perspective); ii) proportion of infectious travelers detected on day of travel (individual perspective).
Read 12 tweets

Did Thread Reader help you today?

Support us! We are indie developers!


This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Don't want to be a Premium member but still want to support us?

Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal

Or Donate anonymously using crypto!

Ethereum

0xfe58350B80634f60Fa6Dc149a72b4DFbc17D341E copy

Bitcoin

3ATGMxNzCUFzxpMCHL5sWSt4DVtS8UqXpi copy

Thank you for your support!

Follow Us on Twitter!

:(