How vaccines help to prevent drug resistance

Drug resistance is a global problem that is threatening the wellbeing of people in many countries, including Kenya.

The resistance usually occurs when micro-organisms or disease causing bugs (such as bacteria, viruses, fungi and parasites) change in ways that render the medications used to cure the infections they cause ineffective.

This is a major concern to health experts because a resistant infection can easily spread and kill people, leading to huge costs for individuals and society.

In Kenya for instance, studies have shown that an increasing number of bacterial infections – such as pneumonia, tuberculosis, drug poisoning and gonorrhoea – are now becoming harder and sometimes impossible to treat as antibiotics become less and less effective.

To address this challenge, the World Health Organisations cautions people against the inappropriate use of medicines such as taking antibiotics for viral infections like a cold or flu.

Getting right prescriptions, finishing drug doses and avoiding low quality medicines (counterfeit or substandard ones) also helps to fight drug resistance.

Aside from these interventions, a new study published in the “Nature Journal” indicates that childhood vaccination may be a powerful tool in the fight against antibiotic resistance in low- and middle-income countries like Kenya.

The research, which was led by scientists from the University of California (UC) Berkeley notes that vaccines guard against bacterial infections.

This minimises the use of antibiotics hence reducing the chances of the drugs becoming ineffective against bacterial infections.

The World Health Organisation (WHO) discourages the overuse of the drugs as it increases the exposure or interaction of bacteria to existing antibiotics.

This makes it easier for the bugs to “study” the drugs and devise ways of resisting their toxic effects.

Despite the significant role that immunisation plays in forestalling drug resistance, the researchers note that the effects of vaccination on antibiotic consumption remain poorly understood— especially in low and middle income countries (LMICs), where the burden of antibiotic resistance is greatest.

The new study therefore, sought to fill this knowledge gap so as to fight drug resistance.

It found that immunising children with two common vaccines (pneumococcal conjugate and rotavirus) significantly reduces the rates of acute respiratory infections and diarrhoea among small children in low and middle-income countries.

“And, with fewer children getting sick or severely sick, fewer are receiving antibiotic treatment,” the researchers noted.

The pneumococcal conjugate vaccines offer protection against a bacterium known as Streptococcus pneumonia (pneumococcus), which can cause life threatening respiratory conditions like pneumonia, ear infections, sepsis (blood poisoning) and meningitis.

On the other hand, the rotavirus vaccines offer protection protect against diarrhoeal infections caused by rotavirus.

Even though the rotavirus infection itself is not treatable by antibiotics, diarrhoea caused by rotavirus is hard to distinguish from the one caused by bacterial infection.

As such, many children with rotavirus diarrhoea usually receive antibiotic treatment even if it is not needed, thus contributing to the misuse of the drugs.

Based on the results of the study, which used data from health and demographic surveys of 78 low- and middle-income countries, pneumococcal and rotavirus vaccines prevent an estimated 19.7 percent of antibiotic-treated acute respiratory infections and 11.4 percent of antibiotic-treated episodes of diarrhoea in children under five years old.

“Right now, almost all countries have developed or are in the process of developing national action plans to address the crisis that antibiotic resistance poses to their health systems, but there is very little evidence addressing which interventions are effective,” said Joseph Lewnard, an assistant professor of epidemiology at UC Berkeley, and lead author of the study, which was sponsored by the Bill and Melinda Gates Foundation.

“By providing hard numbers on the substantial impact that has been achieved with just these two vaccines alone, our work demonstrates that vaccines should be among the interventions that are strongly prioritised.”

He noted that the effects of pneumococcal conjugate and rotavirus immunisations on antibiotic use and antimicrobial resistance have not been included in economic assessments of the value of the two vaccine programmes.

“As low- and middle-income countries make decisions around maintaining or introducing these vaccination programmes, it’s very important to have evidence that demonstrates the impact these vaccines are having domestically.”

By combining data on the effectiveness of the two vaccines with current vaccination rates, the research team further projected that the immunisations are now preventing 23.8 million and 13.6 million episodes of antibiotic-treated acute respiratory infections and diarrhoea respectively each year, among children under the age of five in low and middle income countries.

According to the researchers, if universal vaccination was achieved, an additional 40 million cases of antibiotic-treated illness could be prevented each year, they predicted.

In Kenya, immunisation coverage is currently at 79 percent. However, this national figure hides regional disparities in the uptake of childhood vaccines.

For instance, whereas coverage is at a high of 90 percent in the Central region, the number of children that have received all basic vaccinations is only 51 percent in the North Eastern Region.