Answer:

A child's exposure to a classmate with hand-foot-and-mouth disease does not guarantee infection. If the child is currently healthy, without fever, mouth ulcers, skin rash, or blisters, and shows no suspicious symptoms, a doctor can screen them and recommend vaccination if they meet the health requirements.

When bringing a child to a vaccination facility, parents should proactively inform the doctor about the timing and extent of the child's exposure to the infection source for careful assessment before a decision is made.

Regarding protective efficacy, parents should not expect immediate prevention from the vaccine right after injection. The body's immune system requires a specific period to recognize antigens and produce protective antibodies. Therefore, if the child has already contracted the virus from previous classroom exposure and is in the incubation period, this dose may not generate immunity in time to prevent the incubating illness from developing.

However, vaccination at this time still offers significant long-term protective value. The injection will help the child proactively establish a protective shield against the dangerous EV71 strain for future exposures, according to the recommended vaccination schedule. Parents can also rest assured that the vaccine will not worsen the child's condition if they are in the incubation period. The EV71 hand-foot-and-mouth vaccine is a whole-cell inactivated vaccine, with the virus completely inactivated by formaldehyde, meaning it cannot replicate or cause illness in the body.

Minh An, two years old, is taken by her parents for hand-foot-and-mouth vaccination at VNVC Binh Thuy, Can Tho. *Lam Anh*

After vaccination, families still need to closely monitor the child's health during the period when symptoms from previous exposure might appear. If the child shows signs of fever, blisters, rash, or unusual fussiness or startled reactions, parents should immediately take them to a medical facility and clearly report their history of exposure to the case.

The hand-foot-and-mouth vaccine has been implemented by the VNVC Vaccination System since September 25. The vaccine is for children aged two months to under six years and consists of two or three doses, depending on the child's age at the start of vaccination, with the first two doses administered approximately two months apart.

Additionally, because the vaccine specifically prevents the EV71 strain but does not protect against all other hand-foot-and-mouth disease agents like Coxsackie A16 or A6, parents should continue routine preventive measures after their child is vaccinated. These include washing hands with soap, disinfecting toys, cleaning contact surfaces, and minimizing exposure to community infection sources.

Doctor Huynh Tran An Khuong

Medical Manager, VNVC Vaccination System

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