A new study has said that vaccination against a single strain of Zika virus is sufficient to protect against its genetically diverse strains. The study was conducted by researchers from the Washington University and Emory University in the US. The findings were published in the journal Cell Reports.
There are two distinct genetic lineages of the Zika virus. These are African and Asian. According to the researchers, the Zika virus strain circulating in the current outbreak affecting Central and South America and the Caribbean is of the Asian lineage. When individuals are infected with Zika virus, their immune systems produce neutralising antibodies to fight the infection. These antibodies may offer immunity against future infections by strains of the same Zika virus lineage. Until now, it was unclear whether the antibodies could also protect against infection with strains of the other Zika virus lineage. Results from laboratory experiments and tests in mice now show this may be possible. Such protection indicates that, despite being genetically distinct, all strains of Zika virus have identical surface antigens and therefore are the same serotype.
Researchers studied serum samples from people infected by Zika virus strains circulating in South America and mixed them with multiple strains of the virus in the laboratory to see how well the serum antibodies neutralised the virus. Results showed that antibodies elicited after infection with Zika virus strains of the Asian lineage were able to potently inhibit both Asian lineage and African lineage strains. The researchers also conducted similar experiments using serum samples from mice and found that sera from mice infected with either Asian or African Zika virus strains were equally effective in neutralising virus strains from either lineage.
Speaking about this, the researchers said, The findings are important to the ongoing effort to rapidly develop a preventive Zika vaccine. Because there is only one Zika virus serotype, antibodies elicited by any Zika virus strain in a vaccine could conceivably confer protection against all Zika virus strains.