Researchers have found that immunity from earlier Covid-19 vaccines and infections is largely ineffective against new variants of the virus, including highly mutated Omicron sublineages like EG.5.1 and BA.2.86.
The study, conducted across 17 Kenyan counties and tested at institutions such as Kemri-Wellcome Trust and Kemri-CDC, revealed that over 40% of vaccinated individuals failed to neutralize these variants, while fewer than 20% of those with immunity from past infections showed effective antibody responses.
The research, published in the BMC Infectious Diseases Journal on December 28, highlighted the rapid mutation of SARS-CoV-2, resulting in variants that evade pre-existing immunity and demonstrate increased transmissibility and severity.
Despite being endemic, Covid-19 remains a significant health risk, particularly for older adults and individuals with medical conditions. The disease has led to thousands of deaths globally and in Kenya, where about 5,000 fatalities were recorded until 2023.
Kenya’s vaccination campaign, launched in 2021, saw only 30.7% of adults fully vaccinated by mid-2022, primarily with monovalent vaccines targeting the original virus strain. Vaccine hesitancy and limited access also hampered the program’s success.
The study calls for revised strategies, including updated vaccines targeting current variants and improved genomic surveillance. Researchers expressed concern about Kenya’s reduced monitoring of the virus, with most genomic data originating from Kilifi and Nairobi counties.
The findings underscore the urgency of enhancing Kenya’s Covid-19 response, particularly for vulnerable populations, to mitigate immune escape and protect public health.
