Doctor Pham Dinh Dong, Medical Manager of the VNVC Vaccination System, stated that viruses and bacteria can attack the cardiovascular system through various mechanisms. In addition to directly attacking tissue cells, leading to myocarditis and pericarditis, pathogens can cause inflammation, increasing the risk of rupturing atherosclerotic plaques and forming blood clots, causing myocardial infarction.

Doctor Dong highlighted the cardiovascular complications from the 5 diseases mentioned above and their respective preventive vaccines:

Dengue fever

Medical literature has documented numerous cases of dengue fever with cardiovascular complications. A post in the European Heart Journal in 4/2024 cited the case of a 50-year-old female patient who died from dengue fever complicated by myocarditis while traveling in Thailand. Another study published in the US National Library of Medicine indicated that 12.5% of severe dengue patients experience cardiovascular complications.

Vietnam currently uses the Qdenga vaccine for children aged 4 and older and adults, which helps prevent all four serotypes of the disease-causing virus: Den-1, Den-2, Den-3, and Den-4. The vaccine helps reduce the risk of contracting dengue fever and hospitalization by more than 80% and 90%, respectively. The vaccination schedule consists of two doses, three months apart. Women should complete the vaccination schedule at least one month, and ideally three months, before pregnancy.

A 17-year-old patient with myocarditis caused by influenza B virus. Photo: *Tam Anh General Hospital*

Influenza

Many studies indicate that influenza causes complications such as an increased risk of myocardial infarction, pericarditis, and pericardial effusion. Research on the records of more than 23,400 patients hospitalized for severe influenza from 2008 to 2019, published by Dutch experts in 2024, showed that influenza patients have a 6-fold increased risk of myocardial infarction in the first week of illness.

An article published on the official website of UCLA Health, part of the University of California, Los Angeles (USA), indicates that for every 8 adult patients hospitalized, one experiences serious cardiovascular complications, with a 7% mortality rate.

Influenza can be prevented with various vaccines, including those from France, the Netherlands, South Korea, and Vietnam. The vaccines are administered to children from 6 months of age and adults. Children under 9 who have not been vaccinated need two basic doses, at least one month apart, followed by an annual booster. Adults receive one dose and an annual booster. The influenza vaccine can reduce the risk of heart attacks in people with coronary artery disease by up to 45%, while also reducing mortality rates from heart failure and myocardial infarction.

Pneumococcal disease

*Streptococcus pneumoniae* bacteria are a leading cause of pneumonia and meningitis. More than 90% of pneumococcal deaths occur in developing countries.

According to research published in the US National Library of Medicine in 2020, up to 30% of patients hospitalized for invasive pneumococcal disease experience cardiovascular events, including: arrhythmias, myocardial infarction, and heart failure. The mortality rate in patients with pneumococcal pneumonia and cardiovascular complications is more than double that of those with pneumonia alone.

Doctor Dong said that vaccines are available for many common strains of *Streptococcus pneumoniae*. The pneumococcal 10 vaccine is for children from 6 weeks to under 6 years old. Pneumococcal 13 and 15 are for children from 6 weeks old and adults. Pneumococcal 20 is for people aged 18 and older, and pneumococcal 23 is for children from 2 years old and adults. Depending on age and vaccination history, doctors will advise on the appropriate vaccination schedule.

An article published on Oxford Academic in 2020 indicated that those vaccinated against pneumococcal disease reduced their risk of cardiovascular events by over 14% and their risk of death by 8% compared to unvaccinated individuals.

People receive vaccinations at the VNVC Vaccination System. Photo: *Hoang Duong*

Diphtheria

According to Doctor Dong, myocarditis as a complication of diphtheria can occur about a week after respiratory symptoms appear. Children under 5 and adults who have not been vaccinated or lack booster shots, people with weakened immune systems, and those living in crowded environments are at high risk of contracting diphtheria.

There are several combination vaccines that include a diphtheria component for children and adults such as: 6-in-1; 5-in-1; 4-in-1 against diphtheria-tetanus-pertussis-polio; 3-in-1 against diphtheria-tetanus-pertussis; and 2-in-1 against diphtheria-pertussis.

Young children, after completing the basic doses before the age of two, need a booster shot at 4-6 years old and 9-10 years old, and then every 10 years. Adults who have not been vaccinated or have an unclear vaccination history need to complete three basic doses, followed by a booster shot every 10 years.

Shingles

Research published on Oxford Academic showed that 71,912 people with shingles had a 1.35 times higher risk of myocardial infarction in the first 30 days compared to 2,093,672 uninfected individuals.

Shingles occurs after a person has had chickenpox. To prevent shingles, Doctor Dong recommends that people get both chickenpox and shingles vaccines. A large study noted that the shingles vaccine can reduce the risk of general cardiovascular events by 23%, including a 26% reduction in the risk of stroke, myocardial infarction, or death from cardiovascular disease; a 26% reduction in the risk of heart failure; and a 22% reduction in the risk of coronary artery disease.

The shingles vaccine is indicated for people aged 50 and older, and those aged 18 and older at risk of developing shingles. The vaccination schedule consists of two doses, 1-2 months apart. The effectiveness of disease prevention is up to 97%, reducing the complications of postherpetic neuralgia and other complications by more than 90%. The chickenpox vaccine is currently indicated for children from 9 months of age and adults, with a two-dose schedule, 1-3 months apart.

Hoang Yen