A particularly deadly consequence of measles is its erasure of previously acquired immune memory - setting kids and adults up for infections that they shouldn’t be at risk from!
We found for example that measles can eliminate as much as 80% of someone’s previously acquired immunity to other pathogens! science.org/doi/full/10.11…
An expired test will Not aberrantly turn positive just because it's old
Expiry makes lines not show up. Does make them become dark.
So, if using an expired test:
Do Trust a Positive.
Do Not Trust a Negative.
*And note that many tests have had extended expiry dates...
2/
Here is a thread about the extensions to the expiration dates.
Not all tests are extended but many of them have and that means that the dates on the box may be different from the actual expiration date. I write about it here and how to find out