“Breakthrough Cases” of COVID-19 To Be Expected Say Health Officials

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The revelation on Tuesday that 39 Sonoma County residents who were fully vaccinated were later infected with COVID-19 is an expected development according to county and national disease experts.

Although such cases are relatively rare nationwide say experts, they are expected because the main vaccines being used are only 90-95 percent effective in preventing infection. That means, say epidemiologists, that 5 to 10 infections per 100 thousand people fully vaccinated is to be expected.

Significantly say county health officials, monitoring of the 39 “breakthrough” cases has not found any instances in which those people have spread the infection to others they’ve come in contact with.

Sonoma County has so far determined that 2 of the cases are tied to the so called West Coast variant of COVID-19. Other samples from the breakthrough cases are being sent to state labs for genetic sequencing.

So far lab analysis has found 3 variants to be active in Sonoma County. These are 2 west coast variants, and the U.K. variant that is causing spikes in cases in the upper Midwest. So far that variant has not caused a surge in California, and health officials say growing evidence indicates that vaccines now being administered are very effective against the west coast variants.

For its part, deputy county health officer Dr. Kismet Baldwin says Sonoma County will be processing as many of the “breakthrough” cases as possible through the state health lab to determine which variant or variants are responsible for the cases.