A coronavirus variant first detected in South Africa was linked to a 16-fold increase in cases in Zambia within a month, showing it has the ability to spread more swiftly and efficiently than the original strain.
The South Africa mutation, known by scientists as B.1.351, was first detected in Zambia in December.
The daily average of new cases rose from 44 in the first 10 days of that month to 700 in the first 10 days of January, according to a report from the U.S. Centers for Disease Control and Prevention released on Wednesday.
The pace of acceleration for the B.1.351 mutation and other variants is why public-health officials worldwide are urging continuing mitigation strategies, even as many places are seeing lower case rates than any time since March.
The South Africa mutation was first detected in that country in October.
It has since been reported throughout much of the African continent and in at least 24 countries outside of Africa, including the U.S.
As of Tuesday, B.1.351 has been found in 19 U.S. cases, spanning 10 states.
U.S. health officials have pledged to boost genomic surveillance to detect variants, as most routine tests for Covid-19 do not identify specific mutations.
The two vaccines authorized for emergency use in the U.S. work against the variants identified so far, scientists have said, but may be less potent.
“Spread of the B.1.351 variant is of public health concern because of the potential for increased transmissibility and, thus, increases in cases, hospitalizations, and deaths,” researchers wrote in the CDC’s Morbidity and Mortality Weekly Report.
The research comes as the U.S. is also fighting off a mutation that emerged from the U.K.
That variant, known by scientists as B.1.1.7, was first seen in Colorado on Dec. 29, and was detected in 29 U.S. states in less than a month.
Zambia, a country of about 18 million, does not share a border with South Africa but has trade and tourism links that may have contributed to transmission between the two countries, the CDC said.