A skin rash of itchy, blister-like lesions that eventually turns into scabs. The rash may first show up on the face, scalp, and trunk and then spread to the rest of the body. It usually takes about one week for all the blisters to become scabs.

Other typical symptoms that may begin to appear one to two days before rash include:

• Fever
• Tiredness
• Loss of appetite
• Headache

People who have been vaccinated against chickenpox can still get the disease. However, the symptoms are usually milder (sometimes involving only a few red bumps that look like insect bites and mild or no fever). Adolescents and adults are more at risk for severe disease. Women infected during pregnancy may pass the disease on to their babies. People with weakened immune systems are also at risk for complications.

The virus spreads easily from people with chickenpox to others who have never had the disease or been vaccinated. The virus spreads mainly by touching or breathing in the virus particles that come from chickenpox blisters, and possibly through tiny droplets from infected people that get into the air after they breathe or talk, for example.

The Varicella-zoster virus also causes shingles. Chickenpox can be spread from people with shingles to others who have never had chickenpox or received the chickenpox vaccine. This can happen if a person touches or breathes in virus from shingles blisters. In these cases, a person might develop chickenpox, not shingles.

The incubation period is usually 14-16 days with a range of 10-21 days.

Chickenpox is also known as varicella. It is most contagious five days before the rash appears, especially one or two days before the rash appears. This can last for up to five days after the onset of the rash until it crusts over. People with weakened immune systems may be contagious for a longer period of time.

Varicella vaccine can prevent this disease. Currently, two doses of vaccine are recommended for children, adolescents, and adults. Children should receive two doses of vaccine—the first dose at 12-15 months and a second dose at 4-6 years old.

• Chickenpox Vaccination: What Everyone Should Know
  • Center for Disease Control and Prevention (CDC)
     
• Varicella Vaccination Information for Healthcare Professionals
  • Center for Disease Control and Prevention (CDC)
     
• Varicella (Chickenpox) – Preventative Measures for Travelers
  • Center for Disease Control and Prevention (CDC)

• Investigation Guidance
• Investigation Forms

If you think your child has chickenpox, keep them away from school or childcare until the scabs on their skin are dry or 24 hours have passed without any new blisters. The Texas Administrative Code (Rule 97.7) explains when sick children should stay home from school.

The incidence of varicella in Texas dropped dramatically in 1999. At the same time, vaccination coverage rose across the state due to school vaccine requirements. Varicella infections have continued to decline through 2018. A total of 972 cases of varicella in Texas during this time was the lowest annual case count since reporting began. Cases increased to 1,291 the following year in 2019. In 2020 the number dropped to 348 cases. Overall, the biggest decrease has been seen in five to nine-year-olds. This age group is the most affected by varicella.

• Varicella Outbreak Identification, Investigation, & Control | Chickenpox (Varicella) Centers for Disease Control and Prevention
• Reporting Forms | Texas DSHS
• Chickenpox (Varicella) Vaccination Centers for Disease Control and Prevention
• Varicella (Chickenpox) – Preventative Measures for Travelers Centers for Disease Control and Prevention

Table I. Reported Varicella Disease and Reported Disease Rates - Texas, 2014-2023

¹ Cases per 100,000 population. Population data for years 2014-2018 is from the Department of State Health Services, Center for Health Statistics. Population data for 2019-2023 is projected

population from Texas Demographic Center’s Texas Populations Projections Program and updated on July 18, 2019. For years 2014 (27,470,110), 2015 (27,695,284),

2016 (28,240,245), 2017 (28,797,290), 2018 (29,366,479), 2019 (29,193,268), 2020 (29,677,668), 2021 (30,168,926), 2022 (30,667,390), and 2023 (31,172,832)

projected population was used.

Additional case data can be found in the Texas Annual Reports.