growstuff The research group are not claiming anything about heard immunity. That conclusion has been reached by others, whoever they may be, they are not named.
It is interesting reading this thread, already people are taking the results of a small survey in one small place and applying it universally and drawing conclusions from it that are just not there.
This is what happens to so much scientific and other research these days, the research team publish a small note in a scientific journal hoping to attract more funding or encourage other teams to do the same research to see if they get the same results. The team are cautious and make no great claims for their research, but a journalist sees the report, knows the subject is of high interest at the moment, writes it up, speaks to a couple of people (Who?, he doesn't say). To attract attention he writes it up as being more than it is, and Yahoo picks it up and runs with it.
Gagajo has reported it, and with good reason, it is an interesting result. But now people on GN are ratchetting it up further, reading the research results, but not the caveats and assuming that the results are much more reliable than they really are and making all kinds of extrapolations from that.
All that has happened is that a reputable university did a small scale survey and got results they hadn't expected, but do not want to make any claims until others have replicated them and an expert in the field, not at that university, has peer reviewed them, that is studied everything from sampling methods, tests done, analysis to write up and agreed with them. In a case like this several peer reviewers would need to check it.
Sorry to be such a deaths head at the feast, but these results are neither a breakthrough, nor a guide to possible future action.