An internal document from the Centers for Disease Control and Prevention (CDC) states that the Delta variant of the coronavirus may cause more severe illness and be as contagious as chickenpox, US media reported on Friday, 30 July.
The internal report by the US health authority also indicates that the Delta variant, which was first identified in India, may spread among vaccinated and unvaccinated people at an equal rate.
The director of CDC, Dr Rochelle P Walensky, had acknowledged on Tuesday that vaccinated people with "breakthrough" infections of the Delta variant carry just as much virus load in their nose and throat, as people who are not inoculated and may spread it just as readily, PTI reported.
However, as per the document, which was accessed by The New York Times, the Delta variant is more transmissible than the viruses that cause MERS, SARS, Ebola, the common cold, the seasonal flu and smallpox.
This means that each infected person can infect eight or nine others, as compared to the common cold, which is transmissible to two other people on average, FIT reported.
Vaccines Effective Against Severe Illness, Not Transmission
The document also notes, "Vaccines prevent more than 90 percent of a severe form of the disease, but may be less effective at preventing infection or transmission," PTI reported.
As a result, breakthrough infections and community transmission is likely if precautions are not taken.
The CDC has also recently reversed its guidelines for inoculated citizens, advising them to continue wearing masks.
The health authority's next step is to "acknowledge the war has changed," the document said.
As per a federal official the CDC is "very concerned with the data coming in that Delta is a very serious threat that requires action now," The New York Times quoted.
Additional data on the variant is expected to be published soon.
The document is reported to be based on data from several studies, including an analysis of a recent outbreak in Provincetown, Massachusetts, which began after the town's Fourth of July festivities.
According to the World Health Organisation (WHO), the Delta variant already accounts for more than three-quarters of sequenced specimens in many nations.
(With inputs from PTI and The New York Times)
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