WHO South-East Asia Journal of Public Health
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Year : 2021  |  Volume : 10  |  Issue : 3  |  Page : 33-35

Impact of the COVID-19 pandemic on immunization and surveillance of vaccine-preventable diseases in the WHO South-East Asia Region

WHO Regional Office for South-East Asia, New Delhi, India

Date of Web Publication26-Feb-2021

Correspondence Address:
Dr Sunil Bahl
WHO Regional Office for South-East Asia, New Delhi
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DOI: 10.4103/2224-3151.309870

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How to cite this article:
Bahl S, Khanal S, Sharifuzzaman M, Liyanage J. Impact of the COVID-19 pandemic on immunization and surveillance of vaccine-preventable diseases in the WHO South-East Asia Region. WHO South-East Asia J Public Health 2021;10, Suppl S1:33-5

How to cite this URL:
Bahl S, Khanal S, Sharifuzzaman M, Liyanage J. Impact of the COVID-19 pandemic on immunization and surveillance of vaccine-preventable diseases in the WHO South-East Asia Region. WHO South-East Asia J Public Health [serial online] 2021 [cited 2022 Jan 21];10, Suppl S1:33-5. Available from: http://www.who-seajph.org/text.asp?2021/10/3/33/309870

  Introduction Top

Immunization programmes in countries of the World Health Organization (WHO) South-East Asia Region have a strong foundation in primary health care, and their capacity to maintain service during the coronavirus disease 2019 (COVID-19) pandemic response is a reflection of public investment in resilient and broader health systems. We summarize in this paper the immunization experience during the pandemic and highlight lessons learnt for continuity of service delivery across programmes, in both the “new normal” and future public health emergencies.

  Background Top

More than 37 million children are born in the WHO South-East Asia Region every year. Immunization systems established in the region were able to reach more than 90%[1] of these infants with three doses of diphtheria–tetanus–pertussis (DTP3) vaccine in 2019. The region has continued to build on its immunization programme to achieve the eight goals laid out in the regional vaccine action plan (RVAP).[2] The region eliminated polio in 2014, and maternal and neonatal tetanus in 2016, and has maintained that status for both since then. Five countries, of the eleven in the region, have achieved measles elimination, and two of these have also eliminated rubella. Immunization remains one of the most important public health interventions for the health and well-being of communities in the region and globally.

Epidemics and pandemics have been known to cause disruption to essential health services, including immunization services, resulting in several unfavourable outcomes. The COVID-19 pandemic is no exception. Disruption of immunization services, even for brief periods, is expected to result in an increase in the number of susceptible individuals and, thereby, increase the risk of emergence of outbreak-prone vaccine-preventable diseases.

  The impact Top

The COVID-19 pandemic has had an impact on the performance of immunization and surveillance for vaccine- preventable diseases in several countries of the region. Routine immunization sessions stopped or were severely affected for varying durations, either nationally or subnationally, in most countries. These disruptions were mostly due to decreased access to services following transportation reductions, physical distancing measures, and concerns of caregivers and health workers about COVID-19 exposure.[3] Although vaccine availability remained adequate, immunization coverage dipped to low levels during the early months following the onset of the pandemic, mainly because of interruptions in immunization sessions. Based on data received from countries by the WHO Regional Office for South-East Asia, nearly 3 million fewer children received DTP3 vaccines between January and June 2020 than in the corresponding period in 2019. A similar decline has been observed for other vaccines. For every 1000 children vaccinated, the first dose of measles vaccine is estimated to avert nearly 16.5 deaths and the second dose an additional 1.9 deaths.[4] The decline in coverage of measles vaccination is likely to result in increased mortality and morbidity due to measles.

Similarly, surveillance for vaccine-preventable diseases was affected by the pandemic. The reporting of vaccine-preventable diseases by countries in the region declined significantly for a combination of various reasons such as repurposing of health workers for COVID-19 response, absence of health workers from work due to COVID-19 infection, lockdown measures and fear of infection among communities.[3] More than 30 000 fewer cases of suspected measles and nearly 19 600 fewer cases of acute flaccid paralysis were reported and investigated between January and October 2020 than in the corresponding period in 2019, leading to a decline in sensitivity of surveillance for measles and polio respectively. Environmental surveillance for poliovirus detection was also affected, with more than 600 fewer sewage samples collected and tested in the region in 2020 than in 2019.

The pandemic also delayed the implementation of mass vaccination campaigns for measles, rubella and polio in the region, delayed the introduction of new vaccines that were planned in countries, and delayed various monitoring and evaluation activities.

  The recovery Top

With support from the regional and country offices of WHO and the United Nations Children’s Fund (UNICEF), as well as other partners, all countries in the region took several actions to revive and resume immunization and surveillance activities. Countries adapted the key guiding principles to continue immunization activities during the COVID-19 pandemic[5] to develop national guidelines and action plans for immunization and vaccine- preventable disease surveillance. These plans were rapidly disseminated to subnational levels for implementation. Infection prevention and control guidelines for use during immunization sessions were developed and implemented in all countries. Plans for monitoring the implementation of national guidelines were also developed and implemented. As a result of these measures, immunization coverage levels improved rapidly and, in most countries, achieved the same levels during July to September 2020 as during the corresponding months in 2019. While performance of the surveillance programme has also shown signs of recovery, the reporting rates for suspected measles and acute flaccid paralysis cases remains below 2019 levels in several countries.

  What next? Top

Priority should be given to maintaining continuity of immunization services under safe conditions that ensure no undue risk to health workers, caregivers or the community. The availability of adequate supplies of personal protective equipment for health workers and effective strategies to communicate about safety during immunization sessions remain important. Country-specific catch-up strategies to reach and vaccinate those missed during the pandemic must be developed while implementing routine immunization programmes. National programmes need to decide on the most appropriate strategy to reach these missed children, depending on the extent of disruption of immunization and the COVID-19 transmission dynamics in the country. Multiantigen catch-up campaigns may have to be considered for areas with prolonged disruptions. Relaxation in the upper age limit for vaccination and flexibility in where and when immunization sessions are conducted will allow missed children to be reached. When planning for catch-up strategies, it will be necessary to consider adequate supplies of vaccines and other logistics, appropriate training of health workers, communication and community engagement. Support for field and laboratory capacities for surveillance of vaccine-preventable diseases remains critical. Alternative and innovative strategies, such as event-based surveillance, may have to be considered, depending on country context. Short- and long-term plans to mitigate the impact of the COVID-19 pandemic on immunization and surveillance activities need to be developed. The role of the national immunization technical advisory group in each country remains crucial not only to provide advice on but also to monitor the implementation of strategies for the revival of immunization and surveillance activities.

  Conclusions Top

Immunization is one of the most cost-effective public health interventions, and its roll-out has also received political support as a merit good. The application of lessons learnt from maintaining continuity with quality and reach during the pandemic provides important lessons for building back better systems for primary health care in the new normal.

Previous disease outbreaks and humanitarian emergencies have underlined the importance of maintaining essential health services such as immunization, and effectively engaging communities in planning and service delivery.[6] Immunization delivery strategies will need to be adapted and should be conducted under safe conditions, without undue risk to health workers, caregivers and the community, as per the guidance documents issued by WHO to protect the population from vaccine-preventable diseases. The gains will have to be sustained, and efforts to mitigate the impact will have to be accelerated and innovative approaches developed to ensure continuity of immunization and surveillance activities, vaccinate the cohorts left out, and resume all halted activities on vaccination, new vaccine introduction and supplementary mass vaccination activities. Monitoring, supervision and evaluation of the programme will remain important to ensure that progress towards the goals of the RVAP remains on track – the focus remains on the regional flagship priorities on measles and rubella elimination – and that the Sustainable Development Goals can be met.

Disclaimer: The views expressed in the submitted article are of the authors and not an official position of the institution to which they are affiliated.

Acknowledgements: The authors would like to acknowledge the national immunization programmes of ministries of health and the WHO country offices of the South-East Asia Region for sharing information on immunization and surveillance performance as well as for actions taken to mitigate the impact of COVID-19 on the programmes’ performance. The authors would also like to thank Dr Sudhir Joshi, Dr Emmanuel Njambe, Ms Uttara Aggarwal and Mr Deepak Dhongde for their support in the collation of the information, as well as Dr Alaka Singh from the Health Systems Development team for a review of the manuscript and useful input.

Source of support: None.

Conflict of interest: None declared.

Authorship: SB and SK conceptualized the paper; MS managed the data and all authors contributed equally to the analysis of the data. SK and SB were responsible for writing the article, and SB, JL and SK were also involved in the final review of the article.

  References Top

World Health Organization. Global Health Observatory data repository. Diphtheria tetanus toxoid and pertussis (DTP3): immunization coverage estimates by WHO region; 2020 (https://apps. who.int/gho/data/view.main.81200?lang=en, accessed 8 January 2021).  Back to cited text no. 1
South-East Asia regional vaccine action plan 2016–2020. New Delhi: World Health Organization Regional Office for South-East Asia; 2017 (https://apps.who.int/iris/handle/10665/272397, accessed 22 December 2020).  Back to cited text no. 2
Eleventh meeting of the WHO South-East Asia Regional Immunization Technical Advisory Group. New Delhi: World Health Organization Regional Office for South-East Asia; 2020 (https://apps. who.int/iris/handle/10665/335831, accessed 8 January 2021).  Back to cited text no. 3
Global vaccine action plan 2011–2020. Geneva: World Health Organization; 2013 (https://apps.who.int/iris/handle/10665/78141, accessed 22 December 2020).  Back to cited text no. 4
Guiding principles for immunization activities during the COVID-19 pandemic: interim guidance. Geneva: World Health Organization; 26 March 2020 (https://apps.who.int/iris/handle/10665/331590, accessed 22 December 2020).  Back to cited text no. 5
Vaccination in acute humanitarian emergencies: a framework for decision making. Geneva: World Health Organization; 2017 (https:// www.who.int/immunization/documents/who_ivb_17.03/en/, accessed 22 December 2020).  Back to cited text no. 6

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