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Chickenpox (Varicella)

Usually mild, sometimes serious. Why paracetamol is fine but ibuprofen and aspirin are not, and whether to vaccinate.

Dr. Sana Fatima Updated 8 November 2026 8 min read Draft · awaiting Dr. Sana's medical review

At a glance

  • Worldwide, there were about 84 million cases and 14,553 deaths in 2019 1.
  • 61–100% of non-immune people who live with a case catch it 1.
  • The rash usually appears 14–16 days after exposure (range 10–21 days) 1.
  • It spreads from 1–2 days before the rash until all blisters have crusted, usually about 5 days after the spots appear 36.
  • Two vaccine doses are about 91% effective, compared with about 69% for one dose 14.
  • 56 countries had introduced the vaccine by 2024 1. Pakistan's EPI does not include the vaccine 7.

What it is

Chickenpox is an infection caused by the varicella-zoster virus. It gives a fever and an itchy rash of blisters, and most children recover within a week. Afterwards the virus sleeps in the nerves and can come back years later as shingles 11WHO position paper on varicella vaccines — WHO Weekly Epidemiological Record, 2025. who.int.

Symptoms

  • Fever, tiredness, poor appetite and headache can start 1–2 days before the rash 1.
  • Spots start on the scalp, face or body, become blisters, and crust within 1–2 days 1.
  • New spots keep appearing for 5–7 days, so spots, blisters and scabs are seen together. There can be up to 500 blisters 122About Chickenpox — CDC, 2024. cdc.gov.
  • The illness lasts 4–7 days and is usually milder in vaccinated children 2.
  • It stays contagious until every blister has crusted 33Clinical Overview of Chickenpox — CDC, 2024. cdc.gov.

See a doctor urgently if

  • Skin around the blisters becomes red, hot or painful, or oozes pus. This can mean a bacterial infection 44How to Treat Chickenpox — CDC, 2024. cdc.gov66Chickenpox — NHS, 2025. nhs.uk.
  • Fever lasts more than 4 days or goes above 38.9°C 4.
  • Breathing is difficult 4.
  • The child is hard to wake, confused, unsteady, or has a stiff neck 4.
  • A newborn baby has chickenpox or has been exposed 6.
  • A pregnant or immunocompromised person has been exposed 46.

Who is most at risk

  • Newborns whose mother gets chickenpox in the 5 days before or 2 days after delivery 3
  • Babies under 1, children over 12, and adults 4. Before vaccines, adults died of chickenpox 20–25 times more often than preschool children 1
  • Pregnant women, and people with weak immunity or on long-term steroids 14

The most common complication is skin infection in children and pneumonia in adults 3. In tropical climates more adults have never had chickenpox 1.

How it is diagnosed

Doctors usually recognise it from the rash, which has blisters at different stages, mostly on the body 1. In unusual or severe cases, a PCR test of a blister swab is preferred 13.

Treatment

  • Home care: fluids, paracetamol for fever or pain, calamine lotion or cool oatmeal baths for itching, and short nails 46.
  • Avoid ibuprofen unless a doctor advises it. NHS and American Academy of Pediatrics guidance links it with serious bacterial skin infections 46, and a 2024 study supports this 1515Pokorska-Śpiewak M, et al. Varicella with bacterial superinfections in children — Eur J Clin Microbiol Infect Dis, 2024. doi.org.
  • Never give aspirin. It is linked to Reye's syndrome, which can cause fatal liver and brain damage 4.
  • Antivirals (such as aciclovir) are used for over-12s, pregnant women, people with chronic skin or lung disease, and people with weak immunity. They work best when started within 24 hours of the rash 4. Your doctor decides whether one is needed and the dose.

Prevention

Vaccine: a live, weakened virus, given on its own or as MMRV. WHO's November 2025 position paper recommends 2 doses: the first from 9 months of age, the second at least 4 weeks later. One dose prevents severe disease but does less to stop the virus spreading. The vaccine is not given in pregnancy 1.

  • Pakistan: the EPI covers 12 diseases, but not chickenpox 77Immunization Schedule — Federal Directorate of Immunization, Pakistan, 2026. epi.gov.pk. The vaccine is available privately: Varilrix (GSK) is listed by Pakistani pharmacies 88Varilrix listing — Oladoc, 2026. oladoc.com, and DRAP approved another brand in October 2025 99BioMinhai varicella vaccine DRAP approval — BioKangtai, 2025. en.biokangtai.com.
  • USA: doses at 12–15 months and 4–6 years 55Chickenpox Vaccination — CDC, 2024. cdc.gov.
  • UK: MMRV replaced MMR from January 2026, with the second dose at 18 months 1010Changes to the childhood vaccination schedule from January 2026 — UKHSA, 2025. ukhsa.blog.gov.uk.
  • Clinicians: using MMRV as the first dose adds about 1 febrile seizure per 2,300–2,700 children 1.

After exposure: giving the vaccine within 3–5 days was 79–100% protective against moderate or severe disease. High-risk people who cannot be vaccinated may get varicella-zoster immune globulin or antivirals 1.

The situation now (2025–2026)

  • Global: WHO's position paper (21 Nov 2025) cites 84 million cases and 14,553 deaths for 2019 1. A GBD 2021 analysis (5 Dec 2025) counted chickenpox and shingles together: 86.7 million cases and 13,931 deaths in 2021, with 67% of deaths in low and low-middle socio-demographic regions 1717Wu Z, et al. Global burden of varicella and herpes zoster, 1990–2021 — Front Public Health, 2025. doi.org.
  • Vaccines: 56 countries were vaccinating, based on 2024 data 1. The UK began on 1 Jan 2026 and is running a catch-up from Nov 2026 to Mar 2028 (UKHSA, 30 Dec 2025) 10.
  • Outbreaks: Bangkok reported 752 cases from 1 Jan to 7 Mar 2026, mostly in school-age children 1313Medical Office Monitors Varicella Outbreak, Reports 752 Cases — Thairath, 2026. en.thairath.co.th. At 9 Polish hospitals, admissions for chickenpox with bacterial infection in 2022–23 were 2.66 times the 2019 level 15.
  • Pakistan: NIH logged 219 suspected cases in week 30 of 2025 and 194 in week 33 of 2026. These are undercounts because Punjab did not report 1111Public Health Bulletin, Week 30 — NIH Pakistan, 2025. nih.org.pk1212Public Health Bulletin, Week 33 — NIH Pakistan, 2026. www2.nih.org.pk. NIH urges stronger surveillance and vaccination 11. A lab study found that cases rose after COVID-19, with outbreaks in Rawalpindi and Islamabad 1818Hanif S, et al. First detection of VZV M4 genotype from Pakistan — Acta Tropica, 2024. doi.org.
  • Seasons: temperate countries see a winter–spring peak 1. We found no published seasonal data for Pakistan.

What the research says

  • Hong K, et al., Pediatric Infection and Vaccine 2024Bayesian network meta-analysis, 25 studies, 49,265 people
    Two doses were 91.3% effective against any chickenpox, compared with 69.0% for one dose. doi:10.14776/piv.2024.31.e9
  • Pokorska-Śpiewak M, et al., Eur J Clin Microbiol Infect Dis 2024retrospective multicentre study, n=458
    Group A strep was found in 31% of the children. Ibuprofen use went with about 4-fold odds of complications, though sicker children may have been the ones given it. doi:10.1007/s10096-024-04944-2
  • Uda K, et al., Vaccine 2023interrupted time-series, about 3.5 million children (Japan)
    Chickenpox fell 45.6% after routine vaccination began. Shingles changed little and was rarer in children born after 2014. doi:10.1016/j.vaccine.2023.06.054
  • Hanif S, et al., Acta Tropica 2024molecular study, 267 samples (Pakistan)
    84% of the 178 confirmed cases came after COVID-19. The M4 genotype, detected in Pakistan for the first time, was linked to more severe disease. doi:10.1016/j.actatropica.2024.107162

Questions parents ask

Can you get chickenpox twice?

It is rare, because one infection usually protects for life 2. The virus can come back later as shingles, which is a different illness 1.

When can my child go back to school?

Once all the spots have crusted over, usually about 5 days after they appeared 6.

Can adults get chickenpox?

Yes, if they are not immune. Adults tend to be sicker, and pneumonia is their most common complication 3. Non-immune adults can have 2 vaccine doses 1.

Is chickenpox dangerous in pregnancy?

It can be. Infection in the first 20 weeks harms 0.4–2% of babies, and infection near delivery can make the newborn seriously ill 1. If you are exposed while pregnant, call your doctor the same day 6.

My child was exposed. What now?

Ask your doctor about vaccination within 3–5 days 1. Babies and anyone with weak immunity should be seen promptly 4.

Should I vaccinate if it is not in the EPI?

WHO recommends 2 doses where chickenpox is a public health problem 1. The vaccine is available privately in Pakistan 89, so talk to your paediatrician.

Myth vs fact

  • MythIt is better to catch chickenpox naturally.
    FactCDC strongly advises against "chickenpox parties", because even healthy children can have severe complications 2.
  • MythIbuprofen is fine for chickenpox fever.
    FactUse paracetamol instead, because ibuprofen is linked with serious skin infections 46.
  • MythA child only becomes contagious once the spots appear.
    FactIt spreads from 1–2 days before the rash 13.

Sources

  1. 1.WHO position paper on varicella vaccines — WHO Weekly Epidemiological Record, 2025. https://www.who.int/publications/i/item/who-wer10047-567-590
  2. 2.About Chickenpox — CDC, 2024. https://www.cdc.gov/chickenpox/about/index.html
  3. 3.Clinical Overview of Chickenpox — CDC, 2024. https://www.cdc.gov/chickenpox/hcp/clinical-overview/index.html
  4. 4.How to Treat Chickenpox — CDC, 2024. https://www.cdc.gov/chickenpox/treatment/index.html
  5. 5.Chickenpox Vaccination — CDC, 2024. https://www.cdc.gov/chickenpox/vaccines/index.html
  6. 6.Chickenpox — NHS, 2025. https://www.nhs.uk/conditions/chickenpox/
  7. 7.Immunization Schedule — Federal Directorate of Immunization, Pakistan, 2026. https://www.epi.gov.pk/immunization-schedule/
  8. 8.Varilrix listing — Oladoc, 2026. https://oladoc.com/pharmacy/medicine/varilrix-1000-pfu-injection-05ml
  9. 9.BioMinhai varicella vaccine DRAP approval — BioKangtai, 2025. https://en.biokangtai.com/News_Details/31.html
  10. 10.Changes to the childhood vaccination schedule from January 2026 — UKHSA, 2025. https://ukhsa.blog.gov.uk/2025/12/30/changes-to-the-childhood-vaccination-schedule-from-january-2026/
  11. 11.Public Health Bulletin, Week 30 — NIH Pakistan, 2025. https://www.nih.org.pk/wp-content/uploads/2025/09/Weekly_Report-30-2025.pdf
  12. 12.Public Health Bulletin, Week 33 — NIH Pakistan, 2026. https://www2.nih.org.pk/wp-content/uploads/2026/08/IDSRS%20Weekly%20Report-33-2026.pdf
  13. 13.Medical Office Monitors Varicella Outbreak, Reports 752 Cases — Thairath, 2026. https://en.thairath.co.th/news/local/2919230
  14. 14.Hong K, et al. Effectiveness of two-dose varicella vaccination — Pediatr Infect Vaccine, 2024. https://doi.org/10.14776/piv.2024.31.e9
  15. 15.Pokorska-Śpiewak M, et al. Varicella with bacterial superinfections in children — Eur J Clin Microbiol Infect Dis, 2024. https://doi.org/10.1007/s10096-024-04944-2
  16. 16.Uda K, et al. Routine varicella vaccination and zoster in Japanese children — Vaccine, 2023. https://doi.org/10.1016/j.vaccine.2023.06.054
  17. 17.Wu Z, et al. Global burden of varicella and herpes zoster, 1990–2021 — Front Public Health, 2025. https://doi.org/10.3389/fpubh.2025.1654535
  18. 18.Hanif S, et al. First detection of VZV M4 genotype from Pakistan — Acta Tropica, 2024. https://doi.org/10.1016/j.actatropica.2024.107162

This page summarises published research for education. It is not a diagnosis or a treatment plan. Always speak to your child's doctor, and go to the nearest hospital in an emergency.

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