Why does Quinvaxem vaccine have many "reactions"?

Although post-vaccination reactions are high and public opinion is "reactive", the health sector still believes that the Quinvaxem vaccine is reliable enough.

One of the important reasons, according to Associate Professor, Dr. Phan Trong Lan (photo), Director of the Pasteur Institute in Ho Chi Minh City, is because the Quinvaxem vaccine has established a strong community immune barrier compared to other acellular technology vaccines.

Disease patterns vary from country to country.

- Sir, many people ask: Why does it have to be Quinvaxem when the producing country does not use it?

+ Associate Professor, Dr. Phan Trong Lan:At the time of licensing (2006), Quinvaxem was a 5-in-1 vaccine, which contained a liquid whole-cell pertussis component, easy to use; a multivalent vaccine that helps reduce injections, waste, storage space, and the risk of infection due to multiple injections; and was the best choice for the vaccination schedule in countries using vaccines with whole-cell technology.

To evaluate the use of vaccines in each country, people rely on four criteria. The first is the burden of disease; the second is immunogenicity - the ability to protect against disease; the third is safety and finally the availability and integration into the health system and socio-economic of each country. Based on these four criteria, each country develops its own vaccine use strategy.

When the World Health Organization (WHO) authorized its use, Quinvaxem had completed clinical trials and was pre-qualified by WHO, and licensed for export by the Korean regulatory agency.

Whooping cough ingredients are likely to cause reactions.

- Do we see it as cheap so we buy it and have to use it?

+ The basic difference between Quinvaxem and other 5-in-1 or 6-in-1 vaccines is that the whole-cell pertussis component causes more reactions than acellular, but only at mild and moderate levels, while severe levels are rare and both are the same. The other components are almost similar. The different pertussis components are acellular technology (selecting bacterial antigens) and whole-cell (still keeping the bacterial structure intact). This is still a controversial issue and is even completely contradictory.

People take their children to get Quinvaxem vaccine (illustrative photo).

Suppose why not include acellular technology for the pertussis component in Quinvaxem to reduce the reaction? To prevent pertussis, each country chooses a technology that is effective in preventing the disease for some countries with a high disease burden, creating more durable immunity, better community immunity, suitable for the vaccination schedule as well as the existing vaccination system.

- But why do we still choose whole cell vaccines because they are riskier than acellular vaccines?

+ Each country chooses a vaccine based on WHO recommendations: For countries that have used whole-cell vaccines, consider switching to acellular vaccines because they must anticipate the possibility of disease outbreaks, ensure resources for booster shots (4-6 years old, 11-12 years old, including shots for pregnant women) and take into account community acceptance when giving booster shots. According to WHO reports, for countries with a national vaccination schedule of four doses or less, whole-cell pertussis vaccines should continue to be administered, and should not be switched. Thus, Vietnam has been administering whole-cell vaccines for more than 30 years and they have been effective. Before 1980, there were more than 96,000 cases of pertussis each year, but after more than 30 years of implementing pertussis vaccination with whole-cell technology vaccines and Quinvaxem, since 2010, the number of pertussis cases each year has always been below three digits, a decrease of more than 1,000 times.

How do countries use vaccines, sir?

+ Each country chooses vaccines with different virus strains, different production technology, and different vaccination schedules, so evaluation is not easy. The main thing is that each country should continue to use the vaccine when it is highly effective. According to WHO's assessment through a survey of 19 countries (four middle-income countries and 15 high-income countries), although there is no global outbreak of whooping cough, it is increasing in some countries.

For example, there are four countries where whooping cough epidemics occur and increase, including Australia, the UK, Portugal, and the US, despite high vaccination rates and multiple booster shots with acellular vaccines. The US still records 10,000 to 40,000 cases of whooping cough each year, with 10-20 deaths. Meanwhile, in Australia, there are 11,000-23,000 cases per year... Chile, which uses whole-cell vaccines, still has epidemics because the vaccination rate in this country is too low.

Why not drop Quinvaxem?

- As you said, a number of Vietnamese children are being vaccinated with acellular pertussis vaccine, is there any concern?

+ We are using whole cell vaccines and have created a strong community immunity, the pathogen does not spread. Currently, 8% of the population is vaccinated with acellular vaccines. According to WHO guidelines in July 2014, studies in Australia, England, Wales and the US, as well as experiments on baboons vaccinated with acellular technology vaccines, show that the ability to protect from vaccinated subjects to unvaccinated subjects through passive infection is very limited. Therefore, community immunity is not guaranteed compared to whole cell vaccines. This shows that the transition from whole cell vaccines to acellular vaccines may be related to the resurgence of whooping cough in some developed countries.

- But why do people still prefer acellular vaccines?

+ When the expanded vaccination program is highly effective, people no longer distinguish between the benefits of vaccination and disease. That is, people do not imagine that disease can occur. At that time, parents are more concerned about swelling, pain, redness, fever... It is the reactions of whole-cell vaccines more than acellular vaccines that directly affect parents, making them choose safety to reduce swelling, pain, redness, fever and so acellular vaccines are "preferred".

Whole cell technology vaccination can create better community immunity and prevent post-vaccination transmission. It is also humane in protecting children who are not yet old enough to be vaccinated (under two months old) and those who have contraindications or delays in vaccination.

Thank you, sir.

According to tintuc.vn