7 ms·

genuinely asking, how do we actually know the delta variant is real, and is the dominant variant causing the current cases? do people actually get tested for sp

genuinely asking, how do we actually know the delta variant is real, and is the dominant variant causing the current cases? do people actually get tested for specific variants, or is it just a generic covid test?

kadoban 5y ago
Not every test will tell you which variant it is, but they do some extra testing here and there to track which variants are spreading.
black6 5y ago
Some small subset of COVID tests are sent to larger labs to perform a more detailed genetic test to determine specific variants. The prevalence of different variants within that set is extrapolated to the population of the region from which it originated. If the lab finds that 87% of the samples from Adam's College are of the Omega Mu strain, then it's assumed 87% of total cases at Adam's College to be Omega Mu variant.
ceejayoz 5y ago
Genomic surveillance; separate from the routine COVID tests, performed on a statistically significant sampling of them. https://www.cdc.gov/coronavirus/2019-ncov/variants/variant-surveillance.html https://www.cdc.gov/coronavirus/2019-ncov/variants/variant-s... https://www.cdc.gov/coronavirus/2019-ncov/variants/cdc-role-surveillance.html https://www.cdc.gov/coronavirus/2019-ncov/variants/cdc-role-...
slimeballsz 5y ago
Delta is fake. The whole fucking thing is fake. Branch Covidians should be thrown out of airplanes at 30k feet over the Pacific.
Herodotus38 5y ago
In Washington state, a percent of positive tests are sent to the dept of health for variant sequencing. You can see the published results by week. Delta has outcompeted every other variant for several months. All covid is essentially delta. See page [pdf] 5 on this: https://www.doh.wa.gov/Portals/1/Documents/1600/coronavirus/data-tables/420-316-SequencingAndVariantsReport.pdf https://www.doh.wa.gov/Portals/1/Documents/1600/coronavirus/... It is updated every Wednesday
kjaftaedi 5y ago
Not all cases are tested for which variant, but those that are are catalogued. I've been watching the delta variant take over the world over the past several months here: https://covariants.org https://covariants.org (dark green is delta)
roywiggins 5y ago
It depends where you live. The UK was an early[0] leader in sequencing a lot of their cases. They hit 600,000 sequenced cases in July[1]. That said, if you just want to know what proportion of the population has delta, you don't need to sequence that many cases. The point of sequencing a large fraction of cases is to catch emerging variants, that wouldn't be likely to be caught otherwise. But to know whether Delta is 30%, 50%, or 70% of cases, you just need a good random sample, not a particularly large one, and I imagine you can do that at the labs where the PCR tests are being run. (at one point, I recall that the UK had a test that matched on three distinct sites on the virus, and they found that one of those sites would turn up negative for a particular variant, so they were able to use that as a proxy for the spread of the variant. I don't remember if that was Alpha or Delta though, and obviously it's no replacement for sequencing) [0] https://cen.acs.org/analytical-chemistry/sequencing/200000-counting-UK-sequenced-cases/99/web/2021/02 https://cen.acs.org/analytical-chemistry/sequencing/200000-c... [1] https://www.gov.uk/government/news/uk-exceeds-600000-covid-19-tests-genomically-sequenced https://www.gov.uk/government/news/uk-exceeds-600000-covid-1...
walterbell 5y ago
UK publishes detailed reports on variant surveillance via genetic sequencing, https://www.gov.uk/government/publications/investigation-of-sars-cov-2-variants-technical-briefings https://www.gov.uk/government/publications/investigation-of-... US does statistical sampling and also prevents patients from being told about variants, https://news.ycombinator.com/item?id=28419280 https://news.ycombinator.com/item?id=28419280
_3u10 5y ago
They sample the swabs and do full sequencing for those selected.
323 5y ago
There are multi tests today which can differentiate between variants without sequencing. There is also a way to differentiate on some RT-PCR tests (but not all), depending on how they are made.
mewpmewp2 5y ago
Also see nextstrain.org for interesting data.
depereo 5y ago
NZ had until recently sequenced 100% of its cases, and used that sequencing information to map person to person infection linkages. This included all of the people in the mandatory 2-week quarantine at the border. So in NZ, yes, every case was tested for specific variants. Delta does seem to be real.

kadoban 5y ago

Not every test will tell you which variant it is, but they do some extra testing here and there to track which variants are spreading.

black6 5y ago

Some small subset of COVID tests are sent to larger labs to perform a more detailed genetic test to determine specific variants. The prevalence of different variants within that set is extrapolated to the population of the region from which it originated. If the lab finds that 87% of the samples from Adam's College are of the Omega Mu strain, then it's assumed 87% of total cases at Adam's College to be Omega Mu variant.

ceejayoz 5y ago

Genomic surveillance; separate from the routine COVID tests, performed on a statistically significant sampling of them. https://www.cdc.gov/coronavirus/2019-ncov/variants/variant-surveillance.html https://www.cdc.gov/coronavirus/2019-ncov/variants/variant-s... https://www.cdc.gov/coronavirus/2019-ncov/variants/cdc-role-surveillance.html https://www.cdc.gov/coronavirus/2019-ncov/variants/cdc-role-...

slimeballsz 5y ago

Delta is fake. The whole fucking thing is fake. Branch Covidians should be thrown out of airplanes at 30k feet over the Pacific.

Herodotus38 5y ago

In Washington state, a percent of positive tests are sent to the dept of health for variant sequencing. You can see the published results by week. Delta has outcompeted every other variant for several months. All covid is essentially delta. See page [pdf] 5 on this: https://www.doh.wa.gov/Portals/1/Documents/1600/coronavirus/data-tables/420-316-SequencingAndVariantsReport.pdf https://www.doh.wa.gov/Portals/1/Documents/1600/coronavirus/... It is updated every Wednesday

kjaftaedi 5y ago

Not all cases are tested for which variant, but those that are are catalogued. I've been watching the delta variant take over the world over the past several months here: https://covariants.org https://covariants.org (dark green is delta)

roywiggins 5y ago

It depends where you live. The UK was an early[0] leader in sequencing a lot of their cases. They hit 600,000 sequenced cases in July[1]. That said, if you just want to know what proportion of the population has delta, you don't need to sequence that many cases. The point of sequencing a large fraction of cases is to catch emerging variants, that wouldn't be likely to be caught otherwise. But to know whether Delta is 30%, 50%, or 70% of cases, you just need a good random sample, not a particularly large one, and I imagine you can do that at the labs where the PCR tests are being run. (at one point, I recall that the UK had a test that matched on three distinct sites on the virus, and they found that one of those sites would turn up negative for a particular variant, so they were able to use that as a proxy for the spread of the variant. I don't remember if that was Alpha or Delta though, and obviously it's no replacement for sequencing) [0] https://cen.acs.org/analytical-chemistry/sequencing/200000-counting-UK-sequenced-cases/99/web/2021/02 https://cen.acs.org/analytical-chemistry/sequencing/200000-c... [1] https://www.gov.uk/government/news/uk-exceeds-600000-covid-19-tests-genomically-sequenced https://www.gov.uk/government/news/uk-exceeds-600000-covid-1...

walterbell 5y ago

UK publishes detailed reports on variant surveillance via genetic sequencing, https://www.gov.uk/government/publications/investigation-of-sars-cov-2-variants-technical-briefings https://www.gov.uk/government/publications/investigation-of-... US does statistical sampling and also prevents patients from being told about variants, https://news.ycombinator.com/item?id=28419280 https://news.ycombinator.com/item?id=28419280

_3u10 5y ago

They sample the swabs and do full sequencing for those selected.

323 5y ago

There are multi tests today which can differentiate between variants without sequencing. There is also a way to differentiate on some RT-PCR tests (but not all), depending on how they are made.

mewpmewp2 5y ago

Also see nextstrain.org for interesting data.

depereo 5y ago

NZ had until recently sequenced 100% of its cases, and used that sequencing information to map person to person infection linkages. This included all of the people in the mandatory 2-week quarantine at the border. So in NZ, yes, every case was tested for specific variants. Delta does seem to be real.