I'm not sure I'm reading the press release the same way you are. This is a notice to clinicians (or maybe laboratories, more specifically) who handle PCR tests to remind them to follow those test's instructions to avoid the potential for false positives. The release doesn't say that all positive PCR tests are invalid unless accompanied by symptoms and a second positive test. It says that clinicians should remember that "careful interpretation of weak positive results" in essential, the "weakness" of the positive results stemming from viral load on the threshold of the test's parameters. Specifically, the release reminds clinicians to do this:
Further, the reminders in this release jive with the WHO's guidance for PCR testing, which they've released since January 2020. Here's a link to the latest edition of it, which was published last September:
https://www.who.int/publications/i/item/diagnostic-testing-for-sars-cov-2
That document from September says basically the same thing that today's reminder notice says:
Not only that, but the last page in the September document is a page-long "checklist to reduce possible cases of false positive rRT-PCR results and handling of equivocal results" that laboratories use when conducting tests.
So I'm not seeing a sea change -- or any change, really -- in the WHO's guidance for PCR testing. But I guess I could misreading those documents. What does everyone else think?