I had noticed over the wkend that several HKers were sharing my previous stories on China's DNA surveillance program in relation to the news that Chinese experts had arrived in HK to conduct covid testing. I spent the past few days speaking to geneticists about this. A thread:

1. Getting a DNA sample from a nasal or throat swab is easy. Scientists can extract a DNA sample and an RNA sample, which cld contain traces of the virus, at the same time. The DNA sample wld be run thru a sequencer to generate a profile, the RNA sample thru a RT-PCR machine

2. Creating a DNA database in HK, akin to the ones in the mainland, would "need a certain factory-style set up, which they probably don’t have in a Hong Kong lab," one geneticist told me. "If you are talking about millions of samples, it’s a big scale operation."

3. Now, the HK govt has promised that the samples would not be transported to the mainland. One genetics expert suggested that HK should allow independent monitors in the lab, akin to election observers. @nytmay asked them to respond to that. They did not reply.

4. The head of a large union representing doctors and HK's Dept of Health told @nytmay she was blindsided by the decision to invite Chinese experts in. She said she was not told about the testing problems in HK and that they could have done it without inviting outside help.

5. I guess there is no real way of knowing that DNA samples are being harvested from COVID tests unless lab workers notice protocol is not being followed. ("Why are we sequencing Y-STR profiles instead of doing standard COVID tests? Why are samples not being destroyed?")

6. But absence of evidence does not mean it's not happening, of course. If you see something wrong in the labs, please get in touch! Overall, I found the debate very interesting, having covered mass testing in several Chinese cities. A great reminder of how special Hong Kong is.

7. Read our story: China’s Offer to Help With Virus Testing Spooks Hong Kong (with thanks to @wang_maya for her input!) https://www.nytimes.com/2020/08/06/business/hong-kong-china-coronavirus-testing.html?smid=tw-share