5 questions about dengue vaccine

Dr. Bach Thi Chinh, Medical Director, VNVC vaccination system, said dengue fever tends to increase at the end of the year due to heavy rain. Recently, Vietnam has a dengue fever vaccine, promptly preventing the disease for children and adults when the weather is rainy and the number of cases increases at the end of the year.

Doctor Chinh answers 5 questions about the new vaccine:

Why do we need to get dengue fever vaccine?

In the past, the rainy season was often the peak of dengue fever due to rapid mosquito breeding. However, due to climate change, urbanization, trade… the epidemic is gradually unpredictable, affecting both children and adults. Hundreds of thousands of people get sick and dozens die every year.

The course of the disease is unpredictable, including shock, fluid leakage, severe bleeding, respiratory failure, multiple organ failure… and death. According to US CDCabout one in 20 people develop severe, life-threatening illness and each person can be infected with dengue four times in their lifetime.

In children, the signs of the disease are easily confused with normal fever. Children do not share, so they can easily become more serious. According to the US National Institute of Medicine, the number of children who die from dengue fever accounts for 25.6% of cases. Infected pregnant women may have miscarriages, stillbirths, and premature births. There is currently no specific medicine, it can only treat symptoms in mild cases and correct pathophysiological disorders in severe cases.

Dengue fever vaccine prevents all 4 serotypes of the disease-causing virus including: Den-1, Den-2, Den-3, Den-4, is more than 80% effective, prevents the risk of hospitalization due to the disease by up to 90%, prevents re-infecting people who have already had it.

Research shows that the vaccine is equally effective in people who have and have had dengue fever. Among them, type Den-2 accounts for a high proportion, is common globally, and is often more severe than other serotypes.

New Qdenga vaccine to prevent dengue hemorrhagic fever, developed by Takeda pharmaceutical company (Japan). This strain provides protection with two doses given three months apart without requiring pre-vaccination disease testing.

How long does it take for antibodies to appear after injection?

Similar to other common types, dengue vaccine (Qdenga) requires an average of two weeks to create protective antibodies. Each person needs to be fully vaccinated to achieve maximum effectiveness.

Given the erratic epidemic situation due to climate change, people need to be vaccinated early and fully.

How safe is the vaccine?

Dengue vaccine was tested on 28,000 people in 26 locations, in 8 countries where the disease is endemic. In May, WHO pre-evaluated and evaluated the safety and effectiveness of Takeda.

Data from clinical trials showed that Qdenga was well tolerated, with no serious safety concerns observed. The rate of post-injection side effects in the Qdenga group was similar to the placebo group. By the end of August, this injection was approved in more than 40 countries, including England, Brazil, Indonesia, Thailand…

Side effects and treatment?

After the first 1-2 days of dengue vaccination, people may experience reactions such as pain at the injection site, headache, muscle pain, discomfort, and erythema at the injection site. The second injection is less likely to cause problems.

Vaccinated people need to follow the principle of monitoring post-injection reactions on site for at least 30 minutes and continue checking at home for 24-48 hours. If there are rare signs such as wheezing, difficulty breathing, rash, paleness, abdominal cramps… you need to go to a medical facility for timely examination and treatment.

Should I abstain after injection?

After vaccination, people should abstain from drinking alcohol so that the immune system can function best. In addition, reactions when drinking alcohol can be confused with anaphylactic shock after injection, making it difficult to monitor and treat promptly.

You need to eat and drink enough nutrients before and after injection. Avoid injecting on an empty stomach, taking nutritional supplements afterwards can help the immune system work more effectively.

On the other hand, you should eat lots of green vegetables and drink enough water. Headache is a common reaction. If you become dehydrated, the condition will become worse. Therefore, after injection, people need to drink lots of filtered water, pure fruit juice, and say no to alcohol and drinks containing a lot of sugar.