ANALYSIS: Why the U.S. Is Underestimating Covid Reinfection

Why the U.S. Is Underestimating Covid Reinfection Hundreds of Americans suspect they contracted covid early in the pandemic and recovered, only to get infected again months later. But because the U.S. does so little genetic sequencing of covid sam… khnjonela Kaiser Health News

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As millions of Americans struggle to recover from covid and millions more scramble for the protection offered by vaccines, U.S. health officials may be overlooking an unsettling subgroup of survivors: those who get infected more than once. Identifying how common reinfection is among people who contracted covid — as well as how quickly they become vulnerable and why — carries important implications for our understanding of immunity and the nation’s efforts to devise an effective vaccination program.

Scientists have confirmed that reinfections after initial illness caused by the SARS-CoV-2 virus are possible, but so far have characterized them as rare. Fewer than 50 cases have been substantiated worldwide, according to a global reinfection tracker. Just five have been substantiated in the U.S., including two detected in California in late January.

That sounds like a rather insignificant number. But scientists’ understanding of reinfection has been constrained by the limited number of U.S. labs that retain covid testing samples or perform genetic sequencing. A KHN review of surveillance efforts finds that many U.S. states aren’t rigorously tracking or investigating suspected cases of reinfection.

KHN sent queries about reinfection surveillance to all 50 states and the District of Columbia. Of 24 responses, fewer than half provided details about suspected or confirmed reinfection cases. Where officials said they’re actively monitoring for reinfection, they have found far more potential cases than previously anticipated.

In Washington state, for instance, health officials are investigating nearly 700 cases that meet the criteria for possible reinfection, with three dozen awaiting genetic sequencing and just one case confirmed.

In Colorado, officials estimate that possible reinfections make up just 0.1% of positive coronavirus cases. But with more than 396,000 cases reported, that means nearly 400 people may have been infected more than once. ...