A new study from the University of California, Berkeley, published in the journal Nature in April 2020, reports that extending vaccination to all children could help resolve antimicrobial resistance - one of the biggest obstacles to effective healthcare in low-income countries. This is the first study to look at how vaccination is related to the use of antibiotics in low- and middle-income countries.
The March of Antimicrobial Resistance
The overuse of antibiotics around the world has led to the rise of antimicrobial resistance in many common pathogens - harmful or disease-producing bacteria, viruses, parasites, and fungi. Resistance to antimicrobial drugs is the acquired ability of certain microbes to overcome or work around these drugs administered to kill or incapacitate pathogens. This makes it challenging to treat frequently seen infections with first-line drugs.
These pathogens that become resistant to the drugs commonly used to combat them are termed 'superbugs', and continue to infect human beings – but now the drugs that previously wiped them out have little or no effectiveness.
Many pathogens have undergone this change, including those that cause sepsis, malaria, tuberculosis, and pneumonia. The effect of this resistance is worst in low- and middle-income countries, as they often find it difficult or impossible to provide adequate funds for both caring for those who are already ill, as well as research and development against new strains of pathogens.
Antimicrobial resistance is mediated by genetic adaptations in a population of micro-organisms with a gene variant that helps overcome or avoid the metabolic inhibition or destructive cellular process caused by the drug in question. Since the infection can no longer be treated with that drug, other potentially more costly and less effective drugs and preventive methods must be used.
How Childhood Vaccination Helps
The new study explores the pivotal role of universal childhood vaccination in the effort to prevent the emergence of antimicrobial resistance in low- and middle-income nations.
The current study discovered that immunization with two vaccines – the pneumococcal conjugate and the rotavirus vaccines – significantly lowered the number of children who contracted acute respiratory infections and diarrhea. This means that fewer children require antimicrobial drugs, which in turn reduces the chances of antimicrobial resistance occurring.
Every country is focused on reducing antibiotic misuse and overuse by national action plans, recognizing the critical danger of antibiotic resistance to their healthcare systems. However, not much evidence exists as to the effectiveness of different courses of action.
Says researcher Joseph Lewnard, an assistant professor of epidemiology at UC Berkeley, and lead author of the paper. "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 prioritized."
Just Two Vaccines
The pneumococcal conjugate vaccine protects against the bacterium Streptococcus pneumoniae , which can cause respiratory infections, ear infections, sepsis, and meningitis. The rotavirus vaccine, on the other hand, protects against rotavirus infection, which mainly causes diarrhea. Antibiotics are ineffective against the rotavirus: however, it is difficult to differentiate between diarrhea caused by bacterial infection. This is why antibiotics are often prescribed and administered to rotavirus patients.
Using demographic study and healthcare data from 78 low- to middle-income nations, the researchers found that an estimated 19.7 percent of respiratory infections and 11.4 percent of diarrhea cases in children, which are usually treated with antibiotics, could be prevented by the pneumococcal conjugate and rotavirus vaccines.
They then used data on the efficiency of the two vaccines and the current vaccination rates and calculated that the vaccinations are currently preventing 23.8 million cases of antibiotic-treated acute respiratory infections and 13.6 million cases of diarrhea each year.
Furthermore, their projections show that with universal vaccination, an additional 40 million cases of antibiotic-treated illnesses can be prevented.
Dr. Lewnard added that these figures were likely underestimated, and the actual results could be much higher.
"We're not accounting for the fact that there are indirect reductions in disease associated with the declining transmission of the pathogens themselves, and that there might be additional benefits in other age groups as well," Lewnard said. "Moreover, we are looking at a narrow spectrum of all pneumococcal diseases, which, further, include ear infections and sinusitis cases that often receive antibiotic treatment."
Of course, antimicrobial resistance can also be prevented by better hygiene and public sanitation, and by cutting down on the use of antimicrobials in agriculture. But research is lacking on a head-to-head comparison of the efficacy of these methods vs. childhood vaccination, according to Lewnard.
Pneumococcal and rotavirus vaccinations are usually administered to young children under the age of two in high-income countries. However, due to the vaccine's relatively high cost and the difficulty of accessing reliable healthcare facilities in low-income nations, they are not always administered there. Institutions and charities around the world are working to remedy this actively: however, as they readily admit, it is a mammoth task.
Proof of Benefit in Economic and Health Fields
As developing countries continue to evolve their health strategies, the current study provides useful concrete proof of the economic benefits of vaccination programs in reducing antibiotic use and antimicrobial resistance. This could help frame policies that support new and existing vaccination programs to enhance public health and strengthen the economy in many ways.