Vietnam Introduces Nasal Flu Vaccine for Children as Respiratory Illness Rises

A new option arrives during a surge in respiratory illness

Vietnam introduced its first nasal spray flu vaccine for children aged 2 to under 18 on October 28, 2026, adding an alternative to injections as hospitals faced rising numbers of respiratory patients. Manufactured by AstraZeneca and delivered through the VNVC Immunization System, FluMist targets three seasonal influenza strains: A/H1N1, A/H3N2 and B/Victoria.

The launch came after Ho Chi Minh City recorded 34,664 acute respiratory infections in one week in mid October, more than 64% above the average for the preceding four weeks, according to the Ho Chi Minh City Center for Disease Control (HCDC). Among samples that tested positive for influenza, nearly 77% contained A/H1N1.

The Vietnamese Government News portal's October 28 announcement describes the vaccine's introduction and the pressures facing children's hospitals. Respiratory illnesses being treated included influenza, adenovirus infections and respiratory syncytial virus (RSV) infections. The new vaccine specifically protects against influenza.

For families whose children fear needles, the practical change is straightforward: a dose is sprayed into the nose rather than injected. Medical screening remains necessary because this vaccine contains weakened live viruses and is unsuitable for some children. Injectable flu vaccines continue to provide an option for younger children and people whose health conditions make the nasal vaccine inappropriate.

How a small spray trains the immune system

FluMist is a live attenuated influenza vaccine. Attenuated means weakened: its viruses are designed to multiply only to a limited extent in the lining of the nose and throat, helping the immune system learn to recognise influenza. VNVC says this can sometimes cause mild symptoms resembling a cold.

Each dose contains 0.2 millilitres, divided equally between the nostrils, with 0.1 millilitres sprayed into each side. Administration should be performed or supervised by medical staff, following screening and vaccination safety procedures.

Dr. Bach Thi Chinh, VNVC's medical director, describes three complementary immune responses. Antibodies called IgA act at the lining of the nose and throat, where flu viruses commonly enter. Antibodies called IgG circulate in the blood, while T cells help recognise and respond to infected cells.

VNVC's FluMist product guidance explains these responses and sets out dosing, precautions and storage requirements. For parents, the central point is that the spray changes how the vaccine enters the body, while the goal remains the same: preparing the immune system to respond to influenza.

What the effectiveness figures mean

VNVC cites a pooled analysis of eight randomised clinical trials involving more than 20,000 children aged 2 to 17. The analysis reported efficacy of 87% to 88% against influenza strains that matched those included in the vaccine. A pooled analysis combines results from several studies to examine a larger group.

Chinh described the findings in a statement carried by the Government News portal. Translated from Vietnamese, she said:

According to research data, the vaccine recorded efficacy against influenza of up to 88% for virus strains similar to those in the vaccine.

In clinical trials, efficacy describes how much vaccination reduced the risk of illness compared with the study's comparison group. Protection in everyday use depends on factors including a child's age and health, and how closely circulating flu viruses resemble those selected for the vaccine.

VNVC also cites another clinical study reporting efficacy of 93.4% to 94.6%. Those figures come from a different study, with its own participants and conditions. The pooled figure of 87% to 88% is the one VNVC highlights for protection against matching strains.

VNVC says that, as of September 2025, the vaccine had been licensed in 34 countries, with more than 200 million doses distributed globally and over 20 years of safety and effectiveness data. AstraZeneca Vietnam chairman and general director Atul Tandon also cited its international use when discussing the Vietnamese launch.

Which children need one dose or two?

Children aged 2 to under 9 who have never received a flu vaccine need two doses, at least four weeks apart. Children in that age group who have previously been vaccinated may need one dose, depending on their vaccination history. A clinician should check the record before deciding the schedule.

Children aged 9 to under 18 receive one dose. Annual vaccination is recommended because flu viruses change and the protection generated by vaccination declines over time. Vaccine composition is updated to match the strains expected to circulate.

The rollout followed several developments in October:

• Early October 2026: Children's Hospital 2 in Ho Chi Minh City recorded more than 2,300 respiratory visits a day on average.
• Mid October 2026: HCDC recorded 34,664 acute respiratory infections in one week, more than 64% above the preceding four weeks' average.
• October 28, 2026: VNVC launched the nasal flu vaccine nationwide for children aged 2 to under 18.
• At least four weeks after a first dose: Children aged 2 to under 9 receiving flu vaccination for the first time become eligible for their second dose.

Families arranging vaccination should bring information about previous flu doses and current medicines. The launch information did not state a price for the nasal vaccine.

Why screening matters before choosing the spray

Children under 2 cannot receive this nasal vaccine. VNVC also lists restrictions for people with weakened immune systems, an absent or nonfunctioning spleen, a leak of the fluid surrounding the brain and spinal cord, or a history of severe anaphylaxis to a vaccine component or a previous flu vaccine.

Children aged 2 to 4 with asthma, or wheezing during the preceding 12 months, are also listed as ineligible. For children aged 5 or older with asthma or a severe flare of wheezing, medical assessment is needed. Children and teenagers taking aspirin or medicines containing salicylates should not receive the nasal vaccine.

VNVC advises caution when a child has an acute illness, a serious chronic condition that is unstable, or substantial nasal congestion. A blocked nose can prevent the vaccine from reaching the nasal lining properly, so a clinician may postpone vaccination or select an appropriate injectable vaccine.

Pregnancy is another reason to choose an inactivated injectable flu vaccine instead, according to VNVC's guidance. Inactivated vaccines contain viruses that have been killed. Children with weakened immune systems may also be directed toward an appropriate inactivated vaccine.

Annual flu vaccination is generally recommended from 6 months of age, except where there is a medical reason to avoid it. Children between 6 months and under 2 years therefore need an age appropriate injectable option. Their exclusion from the nasal vaccine matters because children under 2 are among those at greater risk of flu complications.

Medicines and household contacts can affect the decision

Influenza antiviral medicines can interfere with the weakened viruses in the nasal vaccine and reduce its effectiveness. VNVC lists minimum waiting periods after the last antiviral dose: 48 hours for oseltamivir or zanamivir, five days for peramivir, and 17 days for baloxavir.

Antiviral treatment within two weeks after vaccination can also reduce the vaccine's effect. Families should tell the treating clinician when the child received the nasal vaccine so that treatment and any vaccination follow up can be assessed together.

VNVC advises recipients to avoid close contact with people who are severely immunocompromised for one to two weeks after vaccination because of the possibility of transmitting vaccine virus. Parents should mention household members with severely weakened immune systems during screening.

Common reactions listed by VNVC include a runny or blocked nose, sore throat and fever. Fever is more common among children aged 2 to 6. The guidance says sneezing immediately after administration does not require another dose, and children who feel well can continue normal eating, bathing and activity.

Hospitals show why prevention is urgent

Children's Hospital 2 recorded more than 2,300 respiratory visits a day in early October. At Children's Hospital 1, respiratory illnesses accounted for about 70% of all visits, or roughly seven in every 10. In Hanoi, the National Children's Hospital also recorded rising influenza A visits, including children with pneumonia and respiratory failure.

HCDC's finding that A/H1N1 accounted for nearly 77% of influenza positive samples means it represented about three in every four positive flu tests during the reported surveillance period. The city's broader count of 34,664 acute respiratory infections covered illnesses caused by several respiratory pathogens.

Dr. Truong Huu Khanh, vice chairman of the Ho Chi Minh City Infectious Diseases Association, warned that flu can cause serious complications even in otherwise healthy children. These include pneumonia, inflammation of the brain or heart muscle, and secondary bacterial infections that can progress to sepsis, shock or organ failure.

The World Health Organization estimates that seasonal influenza causes about one billion cases worldwide each year, including 3 million to 5 million severe cases. An international study cited in the government announcement estimated 109.5 million influenza episodes among children under 5 in 2018, with about 870,000 hospital admissions for associated acute lower respiratory infections.

Children's close contact at schools and nurseries gives influenza opportunities to spread. Infection can then reach older relatives and family members with underlying conditions, who face greater risks of severe illness.

Less anxiety for children, strict storage for clinics

Parents described needle anxiety as a reason for considering the nasal option. Nguyen Thi Nhu Ngoc, 35, from Tan Son ward in Ho Chi Minh City, brought her seven year old son, Minh Duc, who was often anxious and uncooperative during injections.

Thanh Tung, 34, brought his two primary school children to VNVC Long Bien in Hanoi. He described their experience:

My two children are afraid of needles, so taking them to get vaccinated is quite a struggle. When I heard about the nasal spray flu vaccine, I wanted to find out more. The doctor instructed my children that they just need to breathe normally while the spray is on, so the process was much easier and more comfortable,

VNVC says it operates nearly 300 vaccination centres across 31 provinces and cities, supported by more than 12,000 medical staff. Tandon said the partnership aims to improve access to suitable prevention options and promote scientific discussion and awareness of vaccination.

Behind the simple administration is a demanding storage process. VNVC's guidance specifies frozen storage between minus 30 and minus 20 degrees Celsius before distribution. After controlled thawing, the vaccine can be kept at 2 to 8 degrees Celsius for up to 15 weeks and must not be frozen again.

VNVC says its cold storage capacity, transport infrastructure and experience introducing vaccines supported its selection as AstraZeneca's deployment partner. Temperature monitoring and control of expiry dates remain necessary throughout delivery to vaccination centres.

Vaccination can still help after flu starts circulating

Dr. Bui Nguyen Doan Thu, deputy head of Internal Medicine Department 1 at Children's Hospital 2, says vaccination can still provide benefits once influenza is circulating. Vaccinating before cases rise is preferable, but families whose children have missed the current season's vaccination can seek advice about an appropriate appointment.

Protective immune responses generally take about two weeks to develop after flu vaccination, Thu said. Children can become infected during that interval. Families whose younger children need two doses should also plan for the minimum four week gap between appointments.

Handwashing, covering coughs and sneezes, ventilating living spaces and avoiding close contact with people who have respiratory symptoms remain useful alongside vaccination. People who are ill should reduce contact with others and wear a mask when they need to go out.

Rapid or difficult breathing, the chest pulling inward during breathing, blue lips or unusual lethargy require urgent medical assessment. The immediate choice for families is to find a suitable flu vaccine with a clinician, while continuing measures that reduce infection at home and school.

Key Points

• VNVC launched AstraZeneca's nasal flu vaccine in Vietnam on October 28, 2026, for children aged 2 to under 18.
• Each 0.2 millilitre dose is divided between both nostrils and targets A/H1N1, A/H3N2 and B/Victoria.
• Children aged 2 to under 9 receiving flu vaccination for the first time need two doses at least four weeks apart.
• Medical screening is essential, particularly for children with asthma, weakened immunity or recent antiviral treatment.
• Ho Chi Minh City recorded 34,664 acute respiratory infections in one week in mid October, more than 64% above the preceding four weeks' average.
• Annual vaccination remains recommended, with injectable vaccines available for people whose age or health makes the nasal option unsuitable.