Vaccination Gap Leaves Adults at Higher Risk of Severe Chickenpox and Complications

Compared with children, chickenpox in adults tends to have a more severe course, often accompanied by high fever, severe muscle aches, and a higher risk of complications such as pneumonia, acute respiratory distress syndrome (ARDS), encephalitis, or sepsis. Doctors warn that many people still treat chickenpox as a minor skin condition, leading to delayed care.

Chickenpox vaccination is described as an effective preventive measure, with protection up to 98% when the full vaccination schedule is completed.

Severe adult cases treated in intensive care

At the Intensive Care Center of the National Hospital for Tropical Diseases, doctors reported multiple adult cases requiring urgent intervention. One example is patient S.V.T. (39, Lang Son).

Before admission, Mr. T underwent intestinal obstruction surgery at a local facility. Immediately after the operation, chickenpox lesions began to erupt on the abdomen and rapidly spread across the body, raising the risk of abdominal infection that was difficult to control.

Laboratory results after admission showed CRP rising sharply to 348 mg/L (more than 70 times the normal level). Procalcitonin reached 100 ng/mL, while white blood cells fell to 1.94 G/L, reflecting severe immune exhaustion and widespread infection.

Dr. Nguyen Hong Kỳ, Head of the Intensive Care Unit at the hospital, said the case is particularly complex because an infectious disease outbreak occurred concurrently with surgical complications and septicemia.

Another case involved patient L.V.T. (20, Lao Cai), admitted late after underestimation. By the time of admission, the virus had affected deep internal organs, leading to respiratory failure and acute liver failure in the context of nephrotic syndrome.

Pregnancy case and treatment monitoring

Earlier, the Bach Mai Institute of Infectious Diseases and Bach Mai Hospital also treated a pregnant woman with chickenpox. Patient Q.H (26, Hanoi), in her second pregnancy at 18 weeks, is a kindergarten teacher who had direct contact with a child with chickenpox at work.

After a few days, she developed classic symptoms including persistent fever (38.2°C), fatigue, and headache, followed by vesicular eruptions scattered across the face, chest, and back. Tests confirmed chickenpox, with elevated inflammatory markers (CRP rise), splenomegaly, and a fast fetal heart rate of 177 bpm.

She was admitted and treated with the antiviral drug acyclovir, with close monitoring for both maternal infection and fetal health.

Severe outbreaks linked to lack of vaccination and secondary infection

Doctors noted that a common feature among many severe cases is that the patient has never been vaccinated against chickenpox. Without this immune protection, the virus can spread more aggressively, particularly in people with underlying conditions or weakened immunity.

In Phú Thọ, Cam Khê Rural Health Center reported many cases with secondary infection. The center is treating patient D. (35). Five days before admission, the patient experienced high fever, chills, widespread blistering, fatigue, and poor sleep. Family members treated the patient at home without improvement.

Upon admission, the condition worsened with densely red lesions interspersed with blisters and many pustules. Doctors diagnosed primary chickenpox with secondary infection, a complication that can occur when skin lesions are not properly cared for, allowing bacterial entry.

How chickenpox spreads and seasonal timing

Doctors explained that chickenpox spreads mainly through the respiratory route. The virus transmits via droplets when an infected person talks, coughs, or sneezes, and can linger in the air, entering healthy individuals. This transmission mechanism can trigger rapid outbreaks within communities, with peak outbreaks occurring in hot, humid weather from mid-March to May.

Impact and risk statistics

Dr. Bạch Thị Chính, Medical Director of the VNVC Vaccination System, warned that chickenpox can lead to skin infections, pneumonia, encephalitis, and other complications—especially in adults, where the risk of severe progression is far higher than in children, including acute respiratory failure, septicemia, hepatitis, encephalitis, and even death.

“Studies show hospitalization rates for adults with chickenpox are about 13 times higher and mortality is around 25 times higher than in children. Pneumonia is the most common complication (5–15%), with mortality up to 30%. In pregnant women, the danger is even greater. About 20% of chickenpox cases may lead to pneumonia, with mortality up to 40%.”

Infection during weeks 13–20 of gestation increases the risk of fetal malformation and fetal loss. If infection occurs in the last three months, newborns face up to 30% mortality, and about 15% may develop neuralgia or related complications in early life.

Home-care mistakes and prevention guidance

Beyond immune factors, experts said home-care mistakes can contribute to worsening chickenpox. Habits such as avoiding bathing, avoiding wind exposure, applying leaves, using medications without prescription, or picking at blisters can break down the skin’s protective barrier, enabling bacterial invasion and sepsis.

People are advised not to ignore early signs such as fever, fatigue, or vesicles. When abnormal symptoms appear, they should seek medical care promptly rather than relying on unproven home remedies. For pregnancy planning, experts emphasize proactive prevention before pregnancy, and if fever or rash occurs during pregnancy, medical care should be sought early for timely diagnosis and treatment.

In addition to vaccination, experts emphasized personal hygiene (regular handwashing with soap, using personal items, cleaning and disinfecting living spaces) and controlling underlying conditions such as cardiovascular disease, diabetes, and asthma to reduce infection risk and complications. Infected individuals should be isolated and treated according to appropriate protocols to limit complications and reduce transmission.

Vaccines available in Vietnam

Vietnam currently has chickenpox vaccines including Varilrix (Belgium) for children from 9 months and adults, Varivax (USA) and Varicella (Korea) for children from 12 months and older and adults. Proquad (USA) also protects against measles, mumps, and rubella for children from 12 months and older and adults.

Women are advised to be vaccinated against chickenpox before pregnancy at least 1–3 months prior, depending on the vaccine type.