Public Health England has uncovered a total of 170 confirmed or probable cases of the South Africa variant of coronavirus that appears less susceptible to vaccines.
Routine and surge testing revealed 151 cases in England, six in Scotland and 13 in Wales, according to Dr Susan Hopkins, PHE’s strategic response director, who described the numbers as “reassuring” because they suggest the variant has not taken hold in the UK.
Scientists are keeping a watchful eye on the South Africa variant, named B1351 or 501YV2, because it could undermine efforts to contain the epidemic with vaccines should it spread more widely. Of the 170 cases, 18 are not linked to international travel, suggesting they were caught in the community.
This week, South Africa paused its rollout of the Oxford/AstraZeneca vaccine after the results from a small trial in young people, yet to be published, suggested the jab prevented only 10% of mild or moderate disease caused by the variant.
Public health officials significantly increased testing in parts of the UK last week in a bid to halt the community spread of the South Africa variant and others that are causing concern because of the mutations they carry. Among them are cases of the Kent variant that have evolved a key mutation, E484K, seen in the South African variant and another known as P1 from Brazil. The mutation helps the virus evade the immunity conferred by past infection or vaccination.
On Tuesday, Manchester began surge testing in Hulme, Moss Side, Whalley Range and Fallowfield after four cases of the Kent variant with the E484K mutation were found in two unconnected households. Hopkins said 17 other cases of the variant had now been identified in the UK, with 14 in the Bristol area, which is also surge testing, and three across the country.
The new and emerging respiratory virus threats advisory group (Nervtag) has classed that variant, first identified in Bristol, as a “of concern”, while declaring another found in Liverpool as a “under investigation”.
The latest PHE numbers update those from 3 February, when officials reported 147 confirmed or probable UK cases of the South Africa variant. Hopkins said that if the reproduction number, R, is below 1, neither the South Africa variant nor the Kent variant with the E484K mutation should spread further.
Vaccinating all contacts around clusters of cases was unlikely to work, Hopkins said, because the virus has about a five-day incubation period and it takes 21 days for maximum protection from vaccines to build up. “As we start to release in March, April, May, this will become much more challenging,” she added.
Trials of several vaccines have found reduced efficacy against the South Africa variant. The Novavax vaccine, which is based on similar technology to Oxford’s, had an efficacy of 89% in UK trials, but only 60% in South Africa where 92% of infections were caused by the variant. Likewise, the Janssen vaccine had 72% efficacy in a US trial, but only 57% in South Africa. Both still protected against severe disease, hospitalisation and death.
“We now have direct evidence from clinical trials that vaccines are not as effective in populations where the South African variant is circulating and that is a worry. The vaccines may still protect against severe illness and death, however,” said Ravi Gupta, a professor of clinical microbiology at the University of Cambridge.
Lab work by Gupta and his colleagues suggests that antibody activity generated by the Pfizer/BioNTech vaccine falls nearly 10-fold when the Kent variant acquires the E484K mutation. “It’s absolutely right that PHE are taking this as seriously as the South Africa variant. Until we know more, we need to treat it as if it were the South Africa variant,” he said.
