Impact of COVID-19 pandemic on vaccination campaigns for diseases preventable by vaccine

By Shanet Susan AlexReviewed by Benedette Cuffari, M.Sc.Apr 18 2022

In a recent study published in the International Journal of Infectious Diseases, researchers assess the influence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic on vaccine-preventable disease (VPD) initiatives.

Study: Impact of the SARS-CoV-2 pandemic on vaccine-preventable disease campaigns. Image Credit: aslysun / Shutterstock.com

Background

The coronavirus disease 2019 (COVID-19) pandemic has resulted in an extensive interruption of immunization services worldwide, like the deferral of mass vaccination initiatives. In fact, several independent reports from countries and regions have implied that the current pandemic has also hampered the implementation and planning of mass vaccination campaigns for all VPDs.

Nonetheless, the worldwide impact and progress of vaccination campaign reinstatement following the disruption caused by the current pandemic has not been measured and thoroughly investigated. In May 2020, the World Health Organization (WHO) and partnering nations initiated efforts to track COVID-19-linked interruptions to mass vaccination efforts against measles, cholera, polio, meningitis A, typhoid, yellow fever, and tetanus-diphtheria via the Immunization Repository Campaign Delay Tracker.

About the study

In the present study, scientists analyzed the data derived from the immunization repository campaign delay tracker. This information was used to assess the target population and the number of announced prophylactic and outbreak response vaccination campaigns postponed, scheduled, reinstated, and canceled at four timestamps including December 2021, May 2021, December 2020, and May 2020.

The WHO immunization campaign delay tracker included variables about each vaccination, such as country, United Nations Children's Fund (UNICEF) and WHO region, subnational or national campaign, original implementation date, deferred implementation date, target population size and age range, prophylactic or outbreak response vaccination campaign, other health interventions or co-administered vaccines, and funding source.

The authors compared and analyzed the number of vaccination campaigns postponed and canceled, as well as the primary causes for delay or cancellation at the aforementioned four timestamps.

Study findings

Both prophylactic and outbreak response immunization campaigns were significantly affected by the COVID-19 pandemic across all vaccines. In May 2020, of 183 vaccination efforts in 57 nations, 105 were canceled or postponed because of the SARS-CoV-2 pandemic, with an anticipated 796 million missed or deferred vaccine doses.

The key factors responsible for the disruption of vaccination services during the early phase of the pandemic included inadequate personal protective equipment for healthcare personnel, lack of healthcare professionals, extensive lockdown measures, and vague public health protocol for safe vaccine administration in a mass campaign setting.

Nevertheless, in early July 2020, there was a restart of the immunization campaigns. The percentage of campaigns canceled or postponed because of the COVID-19 pandemic declined from 56% in May 2020 to 16% in December 2021. Further, the fastest resumption rate was observed in the monovalent oral polio vaccine type 2 (mOPV2) initiatives.

Yet, out of 472 immunization campaigns in 54 nations, 77, particularly in African regions, were still canceled or postponed due to the COVID-19 pandemic in December 2021, with nearly 382 million missed or postponed vaccine doses.

The COVID-19 pandemic continues to restrict the surveillance sensitivity and quality of vaccination activities. Resources and personnel have been pushed to meet the heightened demand for SARS-CoV-2 diagnoses. Additionally, some nations have prioritized SARS-CoV-2 vaccine introduction over other immunization initiatives. 

Several countries resumed some vaccinations integrated with infection prevention and control (IPC) measures. Yet, it remains essential to bridge the residual immunity gaps generated by interrupting vaccination programs to avert widespread VPD outbreaks in a health system already overburdened by the SARS-CoV-2 pandemic.

Conclusions

According to the authors, the current study was the most thorough account of how the COVID-19 pandemic impacted mass vaccination efforts presently available.

The study findings demonstrated that COVID-19 wreaked havoc on mass immunization initiatives of all vaccines. The authors believed there is a significant risk of VPD outbreaks because of the heightened number of vulnerable populations resulting from the extensive mass vaccination campaign deferral induced by the SARS-CoV-2 pandemic globally.

Taken together, the present study illustrates that COVID-19 severely interrupted both outbreak response and preventative mass vaccination services among all vaccines, thereby putting millions of children at risk of fatal yet avoidable illnesses. Furthermore, the timely reinstatement of immunization pursuits and an effective catch-up strategy that integrates improved routine immunization campaigns and services are critical in preventing the accumulation of vulnerable individuals and ultimately reducing the risk of disease outbreaks.