Thread by @Ayjchan

On Singapore’s recent delta variant covid cluster: “The cluster’s index case, Case 62873, is an 88-year-old cleaner who worked at Changi Airport Terminal 3. He tested positive on May 5 despite being fully vaccinated.”
channelnewsasia.com/news/singapore…

Another delta cluster in Singapore at a hospital: “A fully vaccinated 46-year-old female nurse at TTSH, or case 62541, became the first case linked to the cluster after she tested positive on Apr 27.”

“In the Delta variant clusters, Prof Leo has seen vaccinated cases with family members who have tested positive. This means it could still be possible for vaccinated people to spread the virus.”

“The experts stressed that new variant strains arise when viruses evolve to adapt and evade human defences”

“Disorganised, half-hearted attempts are exactly the prescription for viral mutants.”

Singapore’s tracking of covid cases is incredible. It’s only when you can clearly follow the chains of transmission that you can understand whether a new variant can infect and be spread by vaccinated individuals (only Pfizer and Moderna in Singapore btw).

The good thing is that full vaccination still confers protection against new variants, even if efficacy is slightly reduced. So it’s very important for people in high risk groups to get vaccinated, especially in places where there are low vax rates and new variants circulating.

For example, did any of the fully vaccinated airport workers who still got infected with the Delta end up transmitting it to other people?

https://twitter.com/Ayjchan/status/1407056624548777988

In India:
“from his experience, he said patients with “reinfections have not landed in the Intensive Care Unit.”
vice.com/en/article/epn…

Very useful covid tracking app for Singaporean cases
h/t @romeo_ph20
covid.viz.sg

@romeo_ph20 Looking at the Bukit Merah market cluster, you can see (if the data is indeed correct) that some vaccinated people are transmitting covid / SARS2 to other people.

Green = fully vaccinated (pfizer/moderna)
Yellow = 1 dose

The selected (blue) vaccinated person is 23 years old.

@romeo_ph20 The selected vaccinated person in this cluster is 39 years old. A chef working at Changi prison.

36 year old dealer at Marina Bays Sands Casino

18 year old national service man at the Civil Defence Academy

The site also tells you who was asymptomatic or symptomatic when they tested positive for covid-19.
For example, in this mini-cluster of 3 fully vaccinated people, the connector person was asymptomatic.

The purpose of getting vaccinated is preventing severe disease/death. And when your community has high vaccination rates, the likelihood of clusters is diminished. This protects the elderly/vulnerable who may not be fully protected even after vaccination.

https://twitter.com/sailorrooscout/status/1404395240136523777

This Covid-tracking app in Singapore is super useful for understanding how transmissible the virus is among vaccinated individuals.
Green = 2 doses
Yellow = 1 dose
The central person is 35 years old. This looks like a workplace cluster. 3 fully vaxed people transmitted to others.

I'm not too worried about vax'ed people being infected because ideally the vaccine would've protective effect. But I'm worried about the people who distrust the healthcare system and refuse to get vax'ed. The virus can spread via vax'ed people. covid.viz.sg

Wanted to give a shoutout to our own site @CovidCg covidcg.org you can track the lineages and variants in each country over time.

For example, Singapore, delta / B.1.617.2 is shown in light blue.
covidcg.org/?tab=group&gro…

In the USA you can see the % of sequenced SARS-CoV-2 that are the delta / B.1.617.2 / Indian (light blue) have also been growing, displacing the alpha / B.1.1.7 / UK (dark blue) over time. Gamma / P.1 / Brazilian is in green.

Not as striking as the UK. Delta has completely overtaken Alpha.

Plotting similar data for other countries, but measured in counts (like for Singapore above) as opposed to % (US and UK above).

Australia, Japan, S Korea, S Africa.

Another way to use covidcg.org is to plot the new % of sequences that are delta variant per month in each country of interest.

For example, in Singapore, 94% of the June sequences were the delta variant. UK 92%, Australia 60%, Japan 46%, USA 23% etc.

Switching the plot to show the new % of sequences that are the alpha variant per month.

The beta variant.