Zika infection is caused by one virus serotype: Study

Vaccination against a single strain of Zika virus should be sufficient to protect against genetically diverse strains of the virus, a study says.

Zika virus strains are grouped into two distinct genetic lineages: African and Asian.

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, said Anthony S. Fauci, Director National Institute of Allergy and Infectious Diseases (NIAID), in the US.

In this study, scientists took 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.

The 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 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.

Such protection indicates that, despite being genetically distinct, all strains of Zika virus have identical surface antigens and therefore are the same serotype.

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, the researchers concluded.

--IANS

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