Discover and read the best of Twitter Threads about #SACEMA
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The latest results from @theSANBS, @The_WCBS, and #SACEMA on anti-SARS-CoV-2 seroprevalence among blood donors in South Africa are now available.
researchsquare.com/article/rs-168…
#notyetpeerreviewed
[1/8]
researchsquare.com/article/rs-168…
#notyetpeerreviewed
[1/8]
Congrats to @laurettemhlanga, @alex_welte, @Marionvermeulen, and the rest of the team!
TL;DR: as of mid-March 2022, prior to the BA.4/BA.5-driven resurgence, an estimated 98% of South Africans had antibodies from prior infection, vaccination, or both.
#notyetpeerreviewed
[2/8]
TL;DR: as of mid-March 2022, prior to the BA.4/BA.5-driven resurgence, an estimated 98% of South Africans had antibodies from prior infection, vaccination, or both.
#notyetpeerreviewed
[2/8]
This round of samples was tested using assays that detect different antibody types.
#notyetpeerreviewed
[3/8]
#notyetpeerreviewed
[3/8]
[Thread] I am pleased to share that this work is now published @ScienceMagazine
science.org/doi/10.1126/sc…
#SACEMA @nicd_sa @hivepi @scienceSUN @NRF_News @carivs @jd_mathbio @GoNevashan @Dr_Groome @saCOVID19mc
science.org/doi/10.1126/sc…
#SACEMA @nicd_sa @hivepi @scienceSUN @NRF_News @carivs @jd_mathbio @GoNevashan @Dr_Groome @saCOVID19mc
We show that reinfection risk (blue) increased with the emergence of the #Omicron variant and has stabilized at a higher level than was seen with prior variants. 
There are two main changes between the published paper and the preprint released in December. First, the published version of the paper has been updated to include data through the end of January 2022.
[Thread] South Africa has seen a recent rapid rise in #SARSCoV2 cases & unprecedented number of reinfections.
We've been working on bounding the levels of transmissibility & immune evasion that could explain #Omicron's spread in 🇿🇦.
sacmcepidemicexplorer.co.za/downloads/Pear…
#NotYetPeerReviewed
We've been working on bounding the levels of transmissibility & immune evasion that could explain #Omicron's spread in 🇿🇦.
sacmcepidemicexplorer.co.za/downloads/Pear…
#NotYetPeerReviewed
We find that #Omicron is likely more transmissible than #Delta. This finding holds across a wide range of assumptions about immune evasion that are consistent with early neutralization studies.
Our analysis includes several steps.
#NotYetPeerReviewed
Our analysis includes several steps.
#NotYetPeerReviewed
First, we analyze trends in S-gene target failure (SGTF) at the provincial level. SGTF is a marker of #Omicron sublineage BA.1. Our updated model accounts for SGTF being an imperfect marker, & we now fit the model to data through 6 December.
[Thread] We have updated our preprint on SARS-CoV-2 reinfection trends in South Africa to include data through late November. @hivepi @jd_mathbio @carivs @Dr_Groome @nicd_sa #SACEMA
doi.org/10.1101/2021.1…
#notyetpeerreviewed
doi.org/10.1101/2021.1…
#notyetpeerreviewed
We find evidence of increased reinfection risk associated with emergence of the #Omicron variant, suggesting evasion of immunity from prior infection. @scienceSUN @NRF_News
We developed 2 methods to monitor signatures of changes in reinfection risk & have used them to monitor reinfection trends in SA since Jan 2021.
@theSANBS, @The_WCBS, and #SACEMA have released new information on SARS-CoV-2 seroprevalence among blood donors in South Africa, including in the 5 provinces for which data were not previously available. #NotYetPeerReviewed
A full preprint will be released soon.
A full preprint will be released soon.
The new data are based on samples collected in May 2021, using the same methods as described in the earlier preprint from Sykes et al:
researchsquare.com/article/rs-233…
The study was led by @Marionvermeulen with data analysis by @laurettemhlanga, Dr Eduard Grebe, and Prof Alex Welte.
researchsquare.com/article/rs-233…
The study was led by @Marionvermeulen with data analysis by @laurettemhlanga, Dr Eduard Grebe, and Prof Alex Welte.
Our preprint about reinfection by the P.1 SARS-CoV-2 lineage in repeat blood donors in Manaus is now out [not peer-reviewed] 🧪🦠🥼🌎
▶️Check it out at: medrxiv.org/content/10.110….
▶️Short thread on key findings🧵 1/10
▶️Check it out at: medrxiv.org/content/10.110….
▶️Short thread on key findings🧵 1/10
It is challenging to estimate the reinfection rate since most reinfected individuals are likely not tested, and/or oligo or asymptomatic. Yet, reinfection has been postulated to explain at least in part the 2nd wave of COVID-19 in Manaus (see bit.ly/3hyjVWk). 2/10
To address this, we tested serial samples from unvaccinated repeat blood donors from Manaus w a seroprevalence assay that wanes during convalescence. We assumed that reinfections induce a boosting ↗️ in antibody (Ab) levels, leading to V-shaped time series of Ab reactivity. 3/10
