Clade 9: chicken-pox variant found in India for the first time

Clade 9, a new variant of the chicken pox variant has been found in India for the first time, officials have said.

Indian virology research institute, The National Institute of Virology (NIV) said it came across clade 9 variants of chickenpox-causing varicella-zoster virus (VZV) whilst looking for mpox (formerly known as monkeypox) cases.

"As part of our surveillance for monkeypox cases, we encountered cases of VZV in the suspected Mpox cases among children and adults,” said Dr Pragya Yadav, senior scientist with ICMR-NIV, and one of the study authors.

Out of 331 suspected cases of mpox, 28 cases were found positive for VZV.

Clade 9 is the most common strain of chickenpox-causing virus in countries such as Germany, UK and the US.

Other variants of VZV, clade 1 and clade, have been previously found in India, but it is the first time that clade 9 has been detected.

The researchers said: "It is critical to distinguish chickenpox from measles, bacterial skin infections, scabies, syphilis, medication–associated allergies, and Mpox viral disease."

According to the World Health Organisation (WHO) the VZV causes highly contagious chickenpox and is generally transmitted through contact with infected droplets, aerosols, or direct contact with respiratory secretions.

It can cause mild symptoms in children and tends to be more severe in adults. The WHO says symptoms such as “an itchy rash, usually starting on the scalp and face and initially accompanied by fever and malaise".

The common symptoms of clade 9 infection include rashes, headache, appetite loss and overall sense of ill health and appear only two to three weeks after exposure to the virus.

In rare cases, VZV can cause severe complications after progressing to the central nervous system of the body.