Medicosnext
Words by Prof. Dr. Ramesh Kant Adhikari
Vaccines and immunization have emerged as one of the main and powerful tools to protect human health from infectious diseases.
Human existence is threatened by various infectious diseases. With the understanding of the role of pathogens as the cause of majority of illnesses or even before this, vaccination has been practiced preventing infections and protecting human beings from serious illnesses. Efforts to prevent smallpox through vaccination in late 18th century were practiced before the human understanding of smallpox virus or an infectious agent as being responsible for the disease. The smallpox vaccine was used to eradicate one of the deadliest diseases humanity had to suffer by 1977 AD.
Human society, encouraged by the success of international collaboration and efforts to eradicate smallpox, embarked on identifying those pathogens which posed significant public health problems and of which elimination, control and eradication were possible. Thus, under the leadership of WHO and UNICEF, a campaign for universal immunization of children was planned with the establishment of national Expanded Program of Immunization (EPI) in 1978 AD. This program was renamed as National Immunization Program subsequently.
Nepal, despite its challenges, stands as an exemplary nation, regularly introducing newer vaccines and achieving high coverage in its immunization program.
Enthused by the success of smallpox eradication; endeavors to eliminate, control, or eradicate various other infectious diseases were strategized. Research in microbiology and vaccine development advances went side by side and helped in such planning. International collaboration in vaccine development, resource mobilization and partnership with national governments played a significant role in this process.
The second virus aimed at eradication was poliomyelitis. The polio plus campaign launched in 1996, resulted in a significant achievement that there has been no polio reported from Nepal since 2010 and South Asia region was declared free of it in 2014. Maternal and Neonatal Tetanus was another disease which has been eliminated in Nepal since 2002 AD. Other diseases which are under control include measles and rubella. There has been a drastic reduction in the incidence of childhood pneumonia, dehydrating diarrheal diseases, meningitis due to Hemophilus influenzae b, diphtheria and pertussis, and hepatitis B infection is also under control.
The advantages of preventing diseases through immunization are manyfold: vaccines protect from infectious diseases, lower the burden on healthcare, save expenditures, and prevent the development of antimicrobial resistance.
COVID-19 pandemic in 2020 posed a significant challenge to the world but at the same time it helped advance the knowledge and capacity to develop and deploy a vaccine within a short period of one year and when employed in conjunction with other public health measures resulted in its control to allow the human activities to proceed normally back again. Thus, vaccines and immunization have emerged as one of the main and powerful tools to protect human health from infectious diseases.
Nepal and immunization program:
The Nepal EPI was launched in 1978 initially only with five antigens (BCG, DPT, TT, Measles and OPV) in 17 districts in 1980 (OPV and Measles had to be provided only through health facilities with cold chain capacity) which was gradually expanded to 63 districts by 1987 and throughout 75 districts by 1990. Initially, the coverage rate was rather low: the Household Health Survey, 1986 had reported that only 11% of children 6-36 months of age were fully immunized and 36.7% were partially immunized.
Since that time, Nepal has achieved significant progress in providing lifesaving vaccines to its population as shown by the following table which shows the gradual introduction and expansion of the coverage as reported in 2022/23:
| Antigen | Coverage (% of eligible children) |
| BCG | 102 |
| Pentavalent (DPT, Hib, HepB) 1 | 101 |
| Pentavalent (DPT, Hib, HepB)3 | 99 |
| Measles Rubella 1 | 97 |
| Measles Rubella 2 | 95 |
| Japanese Encephalitis Vaccine | 95 |
| Typhoid Conjugate Vaccine | 91 |
| Tetanus Diphtheria toxoid | 72 |
| Rotavirus vaccine 1 | 99 |
| Rotavirus Vaccine 2 | 97 |
| Oral Polio Vaccine 1 | 102 |
| Oral Polio Vaccine 3 | 98 |
| Fractionated Injectable Polio Vaccine 1 | 85 |
| fIPV 2 | 64 |
| Pneumococcal Vaccine 1 | 98 |
| Pneumococcal Vaccine 3 | 94 |
PS: Please note that various factors like population changes or catch-up vaccination campaigns may have resulted in some vaccine coverage being above 100%. It is also noteworthy to understand that reaching over 100% coverage doesn’t necessarily mean that every child received the vaccine; it indicates that the number of vaccinations given exceeded the estimated eligible population at the time of calculation.
Immunization Milestones achieved by Nepal
The following table briefly outlines the key milestones in the progress of immunization program in Nepal:
| Year | Milestones achieved |
| 1977 | Smallpox eradicated |
| 2005 | Maternal and Neonatal Tetanus eliminated |
| 2006 | JE Control activities initiated and subsequently controlled |
| 2010 | Last case of polio reported in Nepal; SEA Region certified free of polio in 2014 |
| 2012 | Full Immunization Declaration program started: an unique initiative in Nepal |
| 2015 | National Immunization Program regarded as one of the main contributors in achieving MDG 4 of reducing childhood mortality |
| 2016 | Immunization Act endorsed (first country in SEAR) |
| 2018 | Rubella/CRS Control certification achieved (among first six countries in the region) |
| 2019 | Hep B control through childhood immunization achieved (among first 4 countries in the region) |
| 2020 | MR campaign completed during COVID-19 pandemic, Rota virus vaccine introduced in RI |
| 2021 | COVID vaccine introduced for priority group in January 2021 |
| 2022 | Typhoid conjugate vaccine introduced in NIP |
Despite its low-income status, difficult terrain, political upheaval and natural disasters, Nepal has been hailed as one of the exemplary countries in regularly introducing newer vaccines in its immunization program and achieving a high coverage.
However, several challenges remain such as there are still some population groups who fail to bring their children for immunization, vaccine failure due to faulty cold chain capacity and vaccine stock outs have been identified as important barriers. Efforts to mitigate them are needed. Government agencies will have to take the lead, but non-government organizations, academia and civil societies also must contribute their efforts to address these challenges.
Nepali people have been recognized for their acceptance of new vaccines according to survey reported in “Nature” during the COVID pandemic. This is an encouraging trend which can be used for promoting vaccines in preventing diseases and obviating the need to treat diseases with antimicrobials.
Reasons for promoting the development, deployment, and use of vaccines:
The advantages of preventing diseases through immunization are manyfold: vaccines protect from infectious diseases; obviate the need to seek for health care, thus lowering the burden on health care system, save health care expenditure and the latest advantage that is being recognized is the prevention of development of antimicrobial resistance.
According to WHO, Antimicrobial resistance is emerging as a major threat to human health, and it has been projected that the currently available antimicrobials will not be effective to treat infections by as early as 2050 AD. While 2050 may still appear far, what we all need to understand is, there are been very few antibiotic discoveries since 2000 AD.
Leveraging vaccines is one of the ways to prevent that situation from emerging. To implement this strategy, attention to the following aspects is needed:
- Surveillance for disease prevalence with currently known vaccine preventable diseases and their susceptibility to available vaccines.
- Surveillance for diseases with newer pathogens.
- Effectiveness of currently available vaccines to the pathogens; surveillance for any newer strains emerging and their capability to escape the immunity trap created by current vaccines.
- International collaboration in vaccine development and equitable distribution of vaccines.
- Continuous interaction with community members about vaccines and diseases they prevent, and their health and economic impact.
- Surveillance of adverse events following immunization and take prompt and corrective actions to manage them.
- International partnership in vaccine development and its use.
Some of the initiatives that need to recognize in this field are:
- UNICEF/WHO in promoting EPI program.
- WHO/UNICEF/USAID/World Bank/Rotary International in Polio plus program
- Melinda/Bill Gates Foundation in working with international organizations in introducing new vaccines and making them available in LIC and LMIC.
Conclusion
As we celebrate Nepal’s immunization milestones, it’s crucial to recognize the global imperative in preventing diseases through vaccines. Beyond the immediate protection vaccines offer, they alleviate the strain on healthcare systems, cut expenditures, and crucially, combat the rising threat of antimicrobial resistance—a silent menace that demands our utmost attention now. In this shared endeavor, international collaboration, community engagement, and continuous surveillance will always be key. The alliances formed, including those with UNICEF, WHO, USAID, World Bank, and various foundations, underscore the significance of a united front. The path forward involves not just sustaining current achievements but also proactively responding to emerging challenges.
