Omicron starts faster, has fewer symptoms when re-infected: US CDC

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Omicron starts faster, has fewer symptoms when re-infected: US CDC

The US Centers for Disease Control and Prevention investigated a cluster of omicron infections in the state of Nebraska and found that this type of infection has a rapid onset of symptoms. But, people who become reinfected with a highly contagious form may experience fewer symptoms during their initial encounter with the virus.

The CDC reported the case of six people in the same household with Omicron’s confirmed cases in its latest morbidity and mortality weekly report published Tuesday. Of the six, an illiterate person aged 48 years (index patient) had recently returned from Nigeria. Before his return trip to the US, he tested negative for COVID on 21 November but tested positive on 26 November. The person was first infected with Kovid last year.

After his return from Nigeria, he had uncovered close contacts with five domestic contacts. One household contact was fully vaccinated and had previous symptomatic COVID in 2020, three were uninfected and infected with COVID last year, and one was not vaccinated and had mild upper respiratory symptoms in the previous year, but was not infected with COVID. was tested negative for

While the index patient tested positive on November 26, all six household members aged 11-48 experienced the onset of symptoms during November 24-26. The CDC said the mean interval between the index patient’s earliest potential exposure and symptom onset was 73 hours. Importantly, the CDC found that five patients – all cases of reinfection – described the symptoms and severity of their recent COVID infection as being similar or mild to those during their first infection.

“Five re-infected patients reported symptoms including loss of taste (none), loss of smell (none), and subjective fever (two) compared to those reported during their first infection (four, four, and four, respectively). experienced fewer current symptoms. The unrelated patient without a previous COVID-19 diagnosis experienced cough, joint pain, congestion, fever and chills,” the CDC said. Hospitalization was not required.

“Observations from this investigation suggest a short incubation period,” wrote Lauren Jansen from the Nebraska Department of Health and Human Services in the CDC report. It is “a clinical syndrome similar to or mildly associated with previously described variants in individuals who have been vaccinated or previously infected, and adds to existing evidence that predisposes to reinfection.” suggest an increased capacity”, she said.

Infections with the delta variant have an incubation period of up to 4 days, while the average incubation period in the Nebraska cluster is about 3 days, the report said. So far, infection with Omicron has been reported to be mild in vaccinated patients. However, it is unknown whether the mild clinical syndrome or the different symptom descriptions are the result of existing immune or clinical features associated with omicron infection, the CDC said.

“The five reinfections, including one after full immunization, could be explained by reduced immunity, the possibility of partial immune evasion by omicrons, or both,” Jensen said. More data will be needed to fully understand the epidemiology of Omicron. Type.

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