I have a close friend who both she and her husband got it last August after traveling to Europe and now her whole family (her, her husband, and both of their kids) have it again after traveling, so basically almost exactly a year after their last infection, they have it again. The kids didn’t have it last summer, but I know one of the kids had it in April, so only about 4 months between infections. The other kid had it it earlier in the school year but I don’t remember timing exactly, so less time between infections than the parents but more than the sibling. This go around was less severe symptoms for them than the previous one, mostly just major fatigue this time.
I have family members who had two Covid infections about 6 weeks in between, first infected last May and then infected again last July.
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meta-analysis looking at how protective prior Covid infection is against reinfection published in Feb. 2023 found, “Our findings show that immunity from COVID-19 infection confers substantial protection against infection from pre-omicron variants. By comparison,
protection against re-infection from the omicron BA.1 variant was substantially reduced and wanes rapidly over time. Protection against severe disease, although based on scarce data, was maintained at a relatively high level up to 1 year after the initial infection for all variants.” So basically, the data is showing that pre-omicron, a prior infection protected pretty well against reinfection of pre-omicron variants, but omicron changed the game and post-omicron, protection from reinfection doesn’t last that long, although appears to still be protective against severe disease. This study does’t cover XBB and it’s subvariants which are the currently dominant strains.
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different meta-analysis published in Jan, 2023 looking at the difference between protective effectiveness of prior Covid infection alone versus protective effectiveness of hybrid immunity (vaccine + prior infection) found, “All estimates of protection waned within months against reinfection but remained high and sustained for hospital admission or severe disease.
Individuals with hybrid immunity had the highest magnitude and durability of protection, and as a result might be able to extend the period before booster vaccinations are needed compared to individuals who have never been infected.” They found the hybrid immunity more protective than infection alone. This is all before XBB as well though, so who knows how true this still is.
Until the rate of mutation slows down (which it won’t unless fewer people are getting infected), I think we’re going to just not know how durable any sort of immune protection is going to be from prior infection, vaccination, or hybrid immunity at any moment in time with any sort of confidence. We’ll just be able to look back at the data and figure it out after the fact.