This is an important enough subject to dig into the article in some detail, at least for those who are interested in a bit of a deeper dive.
214 subjects enrolled, 191 who completed at least six separate nasopharyngeal samples in the same season. “Infection” defined as a group of positive weekly samples, allowing for a one week gap for possible false negatives or transient low level shedding.
Subjects consisted of convenience samples of high exposure individuals: children in daycare along with their siblings and parents; high school students and their teachers; workers in the emergency department, and other medical system workers. Not stated in the article but these are groups that should reasonably be expected to be exposed to a variety of common cold causing coronaviruses many times a season each.
Of those 191 in those high exposure groups 105 had no episodes of any coronavirus infections.
Of the 86 who had at least one documented infection as defined 12 were infected with the same germ more than once.
There were no repeat infections with NL63, one repeat of 229E, two with HKU1, and nine with OC43.
9 of the 12 who had repeat infections were in the 1 to 9 year old group, the other 3 were n the 24 to 34 year old group.
3 individuals had infections 3 times: 2 were asymptomatic each and every of the three infections, one listed mild symptoms concurrent with the first episode and no symptoms the two next episodes.
No one had three symptomatic infections.
Of the 191 individuals studied in these high exposure environments 5 had more than one (two) symptomatic infections.
There is (understandably) no data on whether or not those with asymptomatic infections were contagious.
There is (understandably) no data on whether or not the 105 of the 191 who had no episodes of infection had evidence of past infections.
Put another way 2.6% of those in these high/frequent exposure environments, demonstrated more than one symptomatic infection with the same germ in a season. 97.4% did not.
Individuals are free to interpret that as they will, but I personally read the word “frequently” used in the description as a bit inaccurate. The majority of people (55%) in a high exposure environment get no infections at all, 39% got one infection, 6% got infected more than once in a season, and only 2.6% more than once with any symptoms, despite what should presumptively be understood as frequent re-exposure. It is unclear if that 2.6% have some difference in their innate or cellular systems compared to the general population.
Also in the discussion section are some interesting additional mentions:
Studies have previously shown that those experimentally inoculated with 229E and re-exposed a year later DO often get reinfected but with decreased symptoms and with decreased shedding.
In SARS IgG seems to decrease dramatically by 5 years but memory T-cells persist.
I have stated this elsewhere but if natural disease does not provide decent degrees of protection to an individual (and so far, as the article points out, it seems to in at least the short term) then there is very little chance that immunization will do better. Neither should be reasonably expected to provide 100% protection from re-infection, and each re-exposure is a chance to become infected anew, even when the chance of infection is low with each exposure.
Sam Stone Huh? No coronaviruses are not like shingles or HPV and the class does not “lay dormant in people for a long period of time, then flare up” … where did you get that idea?