COVID-19 vaccines developed by Pfizer and Moderna appear to provide significantly less antibody protection against the highly contagious variant that emerged in South Africa, new studies show.
The studies, published Wednesday in the New England Journal of Medicine, indicated that both vaccines elicited much lower levels of neutralizing antibodies against the new strain, compared to the original SARS-CoV-2 virus.
For the Pfizer study, scientists developed an engineered virus that contained the same mutations as the spike portion of the South African variety, known as B.1.351.
Researchers tested the engineered virus against blood taken from people who received the vaccine.
They found that the level of neutralizing antibodies decreased by two-thirds compared to how it performed with the most common version of the virus in US studies.
However, it is unclear whether a reduced antibody response renders the vaccine ineffective against the strain, as it is not known what level is required to neutralize the virus.
“We don’t know what the minimum number of neutralizations is. We don’t have that line, ”said study co-author Pei-Yong Shi.
Meanwhile, the Moderna study found a six-fold decrease in the antibody response against the variant of the vaccine.
The results were published as part of a letter from the Massachusetts-based company in the same journal.
But researchers similarly warned that the effectiveness of the Moderna vaccine against the strain is still not known.
The company has previously said it thinks the vaccine will protect against the variant.
According to the Centers for Disease Control and Prevention, there are currently 19 reported cases of B.1.351 in the United States in 10 states.
With pole wires