chickenpox ( varicella ) is a highly contagious rash illness that is transmitted from patients with either varicella or herpes zoster ( hz ) by direct contact or airborne spread . hz results from the reactivation of varicella - zoster virus ( vzv ) , latently infecting the dorsal root ganglia . localized hz is approximately one - fifth as infectious as chicken pox or disseminated hz . reports have indicated the rare occurrence of airborne transmission of vzv from hz case - patients in healthcare settings . hz case - patients have also been identified as the index case in the outbreaks of varicella . here , we are reporting an outbreak of varicella in the intensive care unit ( icu ) of a tertiary care hospital . a nursing student reported in the outpatient department on 18 march with history of fever for 2 days followed by vesicular lesions on face , chest , and back , which later spread to the whole body . from her history and clinical examination of the lesions , she was suspected to have varicella infection . she denied being in contact with a chicken pox infected case at home or in the hospital , but revealed that she had been attending a patient with hz infection in the pulmonary icu ( picu ) during the last week of february . she was not immune to varicella infection , i.e. , she was neither vaccinated nor had been infected with varicella virus previously . fluid from the blisters was sent for serological examination which later confirmed the diagnosis of vzv infection . two days later , two staff nurses and a medicine resident doctor , also posted in the picu , reported with similar history and clinical manifestations . four more health care workers ( hcws ) ( nurses ) from picu reported with fever and vesicular lesions within 1 week of the first case . all the hcws were started on treatment and granted leave from duty and the matter was reported to infection control committee and the administration . investigation of the outbreak was conducted , and the probable index case was 60-year - old male admitted on february 10 2015 with road side accident , blunt trauma chest , rib fractures with right intercostal drain in situ with right lower zone pneumonia , renal failure , and left ventricular dysfunction . skin lesions in right l2 , 3 , 4 dermatome noticed on february 28 2015 . skin consultation was taken and lesions identified as localized hz , and the patient was started on tab acyclovir 800 mg tds for 7 days and t - bact ointment dressings . the patient had expired before we had first report of chicken pox infection in hcw . a total of eight hcws were infected with vz virus in 3 and 4 week of march . all the infected hcws were directly or indirectly involved in care of the index case . the rest of the susceptible staff ( medical and paramedical ) of picu was vaccinated with chickenpox vaccine . all the old and new patients admitted to the picu during this period were screened and tracked for about 2 months and did not develop any such lesions . on follow - up , no new vzv infection among hcws or patients was reported . chickenpox is highly contagious and the average incubation period is 14 days ( 1021 days ) . persons with varicella are considered infectious from 1 to 2 days before the rash appears and until all lesions are crusted over . an outbreak of varicella is defined as the occurrence of five or more cases in a specific setting that are epidemiologically linked . cases should be considered part of an outbreak if they occur within at least one incubation period ( 1021 days ) of the previous case - patient , and surveillance should continue through two full incubation periods ( 42 days ) after the rash onset of the last identified case - patient to ensure that the outbreak has ended . patients with zoster have been found to be contagious to those who have no immunity to vzv . the route of transmission is via direct contact of the skin or exposure to dressings or clothing soiled with blister fluid from such individuals . therefore , hz is considered far less contagious than its varicella counterpart because the virus is believed to be localized to the skin and does not involve the respiratory tract . current guidelines for prevention of varicella spread from a hz patient state that in all cases , standard infection - control precautions should be followed . they recommend the covering of hz lesions as a means of preventing nosocomial spread and do not recommend the isolation of all affected patients . whereas we are stressing the fact that even localized hz infection can lead to chickenpox outbreak , so probably only contact precautions may not suffice . strategies for managing zoster patients may have to incorporate the same precautions of airborne transmission as with varicella patients to reduce the risk for transmission . vaccination for chickenpox is not included in national immunization schedule , but is recommended by indian academy of pediatrics . chickenpox in adults is more severe than in children , so it is better to get the children vaccinated . unvaccinated vzv exposed healthcare personnel without evidence of vzv immunity should receive postexposure vaccination as soon as possible . vaccination within 35 days of exposure to rash may modify the disease if infection occurred . vaccination 6 or more days after exposure is still indicated because it induces protection against subsequent exposures . for unvaccinated vzv - susceptible healthcare personnel at risk for severe disease and for whom varicella vaccination is contraindicated ( e.g. , pregnant healthcare personnel ) , varicella - zoster immune globulin after exposure is recommended . in the present scenario , now , we have made certain changes in our hospital policy to prevent a future outbreak . healthcare personnel would be alerted to the risks of possible infection and offered 2 doses of varicella vaccine when they begin employment . stringent airborne and contact precautions will be ensured not only in patients suffering from varicella , but also in patients with hz infection in future .
varicella - zoster virus ( vzv ) causes 2 clinically and epidemiologically distinct forms of diseases . 
 chickenpox ( varicella ) is the disease that results from primary infection with the vzv . 
 herpes zoster ( hz ) results from the reactivation of vzv latently infecting the dorsal root ganglia . 
 we are reporting an outbreak of varicella infection among the health care workers ( hcws ) in the intensive care unit ( icu ) of a tertiary care hospital . 
 we found transmission of varicella among eight hcws of pulmonary icu . 
 they had a history of contact with a patient having hz infection . 
 investigation of the outbreak was conducted as per guidelines . 
 better dissemination of information on disease transmission , isolation of infected patients inside the hospital , and adequate protection ( including vaccination ) for susceptible employees are important to prevent such outbreaks .