Operational Considerations for Routine Immunization Services during the COVID-19 pandemic in non-US Settings Focusing on Low- and Middle-Income Countries

Summary of Recent Changes

Key Points

• Adapt immunization strategies to the vaccine-preventable disease risks and COVID-19 situation in your country.
• Engage with communities and implement communication strategies to make people aware that routine vaccines are available.
• Use the immunization information systems in your country to monitor who missed routine vaccines and to inform your catch-up vaccination strategies.

Background

Routine immunization services have been disrupted significantly during the COVID-19 pandemic, threatening achievements in the fight against major vaccine-preventable diseases (VPDs) like polio, yellow fever, and measles. According to new data, 60 lifesaving immunization campaigns are currently postponed in 50 countries, putting around 228 million people – mostly children – at risk for preventable infectious diseases. Over half of the 50 countries affected by these interruptions are in Africa, highlighting protracted inequities in access to critical immunization services ^[1].

Routine immunization is the sustainable, reliable, and timely interaction between the vaccine, those who deliver it, and those who receive it to ensure every person is fully immunized against VPDs. Examples of routine immunizations are childhood vaccination against diphtheria, measles, polio, tetanus, meningitis, pertussis, and adulthood vaccination against flu and tetanus.

In many countries, routine immunization services have been disrupted due to:

• Unavailability of healthcare workers because of their deployment to the COVID-19 response.
• Lack of personal protective equipment (PPE) to conduct immunization activities.
• Healthcare workers’ fear about contracting COVID-19.
• Interrupted supply of vaccines due to COVID-19 related closure of country borders.
• Unwillingness or inability of parents to leave their homes due to fear of COVID-19.

The following guidance is meant to supplement but not replace any local health and safety laws, rules, and regulations. It is intended for CDC country offices, immunization program managers, and staff from partner immunization programs.

Routine immunization services during COVID-19

Routine immunization services such as vaccination against measles, yellow fever, diphtheria, and polio are essential and should be maintained as much as possible during the COVID-19 pandemic to protect children and prevent outbreaks of VPDs ^[2].

Recently, several COVID-19 vaccines were approved or authorized for use in eligible populations. Achieving high and equitable global COVID-19 vaccination coverage remains the highest priority to reduce COVID-19–related morbidity and mortality, and to mitigate the emergence of SARS-CoV-2 variants.

Vaccination delivery strategies need to be adapted depending on the VPD risk and COVID-19 situation in each country (see Provision of Immunization Services section) ^[2]. National Immunization Technical Advisory Groups (NITAGs) should be involved in decision making with regard to scheduling and implementing routine immunization services and mass vaccination campaigns.

Special considerations for setting up routine vaccination sites and maintaining good infection prevention and control (IPC) practices should be followed, including:

• Conduct vaccination in a well-ventilated area and implement disinfection, as needed.
• Reconfigure waiting rooms to allow for at least 2 meters (6 feet) distance between people. In situations where people form lines, encourage people to stay apart by providing signs or other visual cues such as tape or chalk marks.
• Limit entry to only one companion per vaccination recipient.
• Make available alcohol-based hand sanitizer with a minimum of 60% alcohol or a hand washing station with soap and water; ask healthcare workers and every person entering the vaccination site to sanitize or wash their hands.
• Screen recipients and their companions for COVID-19 symptoms before they enter the vaccination site. Refer those who have COVID-19 symptoms to the relevant part of the health system for further COVID-19 evaluation. Offer vaccination at the COVID-19 evaluation site if feasible. If that is not feasible, postpone vaccination until their quarantine period has ended to avoid potentially exposing healthcare personnel and others during the vaccination visit. Schedule individual vaccination appointments for people with pre-existing medical conditions, if feasible.

Recommendations for vaccinators of routine immunizations:

• Vaccinators should not come to work if they have symptoms suggestive of COVID-19 or have been exposed to a person with a laboratory confirmed case of COVID-19. See quarantine and isolation guidelines for further details on when vaccinators can return to work.
• Vaccinators should wear masks with multiple layers of tightly woven, breathable fabric and nose wire that completely cover both nose and mouth throughout the vaccination session, especially in areas with widespread community transmission of COVID-19.
• Vaccinators should wash or sanitize their hands after interacting with each vaccine recipient.
• Vaccinators should get vaccinated against COVID-19 when they become eligible to be vaccinated.

Provision of immunization services in different situations of COVID-19 community transmission

Communities with none-to-minimal transmission of COVID-19 (evidence of sporadic cases or limited community transmission, no evidence of exposure in large communal setting):

• Continue fixed (health facility-based) routine immunization sessions where all country-recommended childhood vaccinations are provided and all newborn vaccinations are provided immediately after birth [such as Bacillus Calmette–Guérin (BCG), oral polio vaccine (OPV) and Hepatitis B birth dose (HepB).
• Continue outreach and mobile immunization sessions if there is no evidence of local transmission.
• Continue routine vaccination at school sites if schools are open and are allowing such activities.
• Offer catch-up vaccination on an ongoing basis to ensure individuals can receive the recommended vaccine doses, especially if the interruption to immunization services is relatively short or in defined populations (e.g., pregnant women).
• Continue mass vaccination campaigns while maintaining standard IPC measures and using PPE.
• Continue VPD surveillance activities as usual.

Communities with minimal to moderate transmission of COVID-19 (sustained transmission with high likelihood or confirmed exposure within communal settings with potential for rapid increase in cases):

• Continue fixed (health facility-based) routine immunization sessions where all country-recommended childhood vaccinations are provided and all newborn vaccinations are provided immediately after birth (such as BCG, OPV, and HepB).
• Consider whether to maintain or temporarily suspend outreach, mobile, and school-based vaccination sessions based on the COVID-19 pandemic control government policy, local epidemiology, and lessons gathered so far on vaccination session implementation.
• Asses the risks and benefits of the based on local VPD morbidity.
• Consider modified approaches to vaccine delivery.
• Identify critical VPD surveillance activities that need to continue, such as eradication and elimination goals.

Communities with substantial transmission of COVID-19 large scale community transmission, multiple cases within communal settings (e.g., healthcare facilities, schools, workplaces, mass gatherings):

• Continue fixed (health facility-based) routine immunization sessions where all country-recommended childhood vaccinations are provided and all newborn vaccinations are provided immediately after birth (such as BCG, OPV, HepB).
• Review government policy for COVID-19 pandemic control, lessons gathered so far on vaccination session implementation, local epidemiology, and implementation feasibility to consider whether to maintain or temporarily suspend outreach, mobile, and school-based vaccination sessions.
• Re-evaluate the routine immunization situations weekly by conducting risk-benefit analyses of continuing to suspend any type of immunization sessions (fixed, outreach, mobile, or school-based) on morbidity and mortality of the VPD against the potential to increase COVID-19 transmission.
• Temporarily suspend mass vaccination campaigns.
• Identify critical VPD surveillance activities that need to continue.
• Suspend community-based surveillance.

Catch-up vaccination

Catch-up vaccination refers to the action of vaccinating an individual, who for any reason (e.g., delays, stockouts, limited access, hesitancy, service interruptions) has not received doses of routine vaccines for which they are eligible per the national immunization schedule ^[3]. Timely vaccination is essential to maintaining population immunity and preventing large outbreaks of VPDs. Health system disruptions caused by acute emergencies, including pandemics such as the COVID-19 pandemic, can interrupt routine immunization services and delay mass vaccination campaigns, leading to missed vaccinations. Though unavoidable, such interruptions can result in a significant accumulation of susceptible persons. Specially planned catch-up vaccination efforts may be needed to close these immunization gaps. A catch-up vaccination strategy is an essential part of a well-functioning national immunization program and should be implemented routinely.

Catch-up vaccination can be conducted through regular fixed routine immunization service delivery (outreach, mobile, school-based), periodic intensification of routine immunization activities ^[3], or national immunization days. If not already in place, catch-up vaccination practices can be integrated into routine immunization service delivery and continue as an essential component of the routine immunization program.

Catch-up vaccination guidelines and schedule

Catch-up vaccination guidelines and a schedule for catch-up vaccinations are essential components of an immunization program. Catch-up policies or guidance should be developed or revised in collaboration with the NITAG and relevant immunization stakeholders. Where guidance is required sooner than the policy development or revision processes can be completed, interim guidance for catch-up vaccination should be issued (e.g., temporary removal of upper age limits to ensure those missed are able to receive the vaccines for which they were due). At the earliest available opportunity, a formal review should be conducted to decide if the interim guidance for catch-up vaccination should be adopted.

National routine vaccination guidelines vary considerably across countries, thus it is not possible to recommend a ‘generic’ catch-up vaccination schedule. Common elements in all catch-up vaccination schedules should include:

• Range of ages for which the catch-up vaccination schedule applies.
• Lower and upper age limits for each vaccine dose, per national policy (may not be applicable for all vaccines).
• Minimum intervals between doses of the same vaccine as recommended by the World Health Organization (WHO).

The WHO developed recommendations for interrupted or delayed immunization and guidance for planning and implementing catch-up vaccination to help inform development of catch-up policies and vaccination schedules. Catch-up vaccination policy guidance and the vaccination schedule should be officially disseminated to all healthcare staff involved in managing and delivering immunization services. Any interim guidance on catch-up vaccination developed because of a health emergency should be coordinated closely with other related emergency response activities and organizations (e.g., WHO Health Emergencies [WHE] program, local or international NGOs) to ensure that it is reflected in any guidance specific to the health emergency.

Considerations for catch-up vaccination efforts

Missed vaccine doses can be provided through a variety of immunization delivery strategies, and the choice of catch-up vaccination strategies will depend on many factors such as:

• Duration and extent of disrupted routine immunization services
• Local epidemiology of outbreak prone VPDs (e.g., measles, polio, diphtheria, yellow fever)
• Size and extent of pre-existing immunity gaps in under-served communities
• Target population needing to be caught up (e.g., age, geography)
• Human resources available
• Vaccine stocks and supplies available
• Financial resources available
• Availability of home-based records
• Local interruptions (e.g., weather, security, political events)

Missed vaccine doses that are provided to persons outside the recommended age range should still be recorded on the home-based record of vaccination and reported through the usual immunization information system. Vaccine doses should always be recorded in accordance with the number of doses in sequence, regardless of age of the recipient. Vaccinators should adhere to the WHO guidelines for interrupted or delayed routine immunization to safely space doses of live vaccines whilst also optimizing the number of different vaccines provided during a single catch-up vaccination encounter. Where multiple doses of the same vaccine are missing (e.g., two doses of polio vaccine), vaccinators should adhere to minimum intervals between doses of the same vaccine to optimize the immune response. See WHO recommendations for minimum intervals for routine immunizations.

Communication Strategies

Engagement with communities and implementation of communication strategies are essential to re-establish community demand for routine immunizations and increase awareness that it is not too late to vaccinate. Healthcare workers should regularly inform communities about the status and availability of routine immunization services and mass vaccination campaigns. Regular communication will help reduce confusion about vaccine availability and increase awareness of the necessary precautions in place at the immunization site to prevent COVID-19 transmission. Key messaging should include:

• Individuals are still eligible to receive their missed vaccinations.
• Late vaccination still provides a high level of protection against disease.
• When and where immunization services are currently being provided.
• Safety precautions being taken for delivery of services.

When catch-up vaccination is disrupted, it is important to monitor the situation as closely as possible throughout the period of disruption. Using national immunization information systems to monitor individuals or cohorts missing routinely scheduled vaccinations will help inform catch-up vaccination strategies.

Monitoring approaches should include:

• Monitoring vaccination coverage, VPD surveillance, adverse events following immunizations, and vaccine safety concerns to identify gaps, inequalities, and disproportionally affected groups.
• Identifying and maintaining a record of the population at the service delivery level, including newborns and infants, with overdue vaccines during the period of disruption.

Following a significant period of interruption or reduction in immunization services, planning for catch-up vaccinations may require additional large-scale intensified and specialized efforts to identify and seek out groups who have missed their routine immunization. Triangulation across data sources (i.e., vaccination coverage and surveillance data) is needed for a comprehensive risk assessment that can inform the need for catch-up vaccination, particularly in deciding the scale and type of catch up strategies. Rapid coverage assessments in areas known to be particularly affected by the disruption may be necessary to identify disproportionately affected communities to prioritize for catch-up vaccination. Known high-risk and low coverage communities (e.g., displaced populations, urban poor, remote and rural, conflict-affected) should remain a high priority for catch-up vaccinations, because of existing inequalities and higher risk for outbreaks ^[3]. For detailed guidance see WHO guidance for closing immunization gaps caused by COVID-19.

References

1. Gavi, WHO, and UNICEF. Immunization services begin slow recovery from COVID-19 disruptions, though millions of children remain at risk from deadly diseases. Available at: https://www.who.int/news/item/26-04-2021-immunization-services-begin-slow-recovery-from-covid-19-disruptions-though-millions-of-children-remain-at-risk-from-deadly-diseases-who-unicef-gavi
2. Framework for decision-making: implementation of mass vaccination campaigns in the context of COVID-19: Interim guidance. Available at: https://www.who.int/publications-detail/framework-for-decision-making-implementation-of-mass-vaccination-campaigns-in-the-context-of-covid-19
3. Leave No One Behind: Guidance for Planning and Implementing Catch-up vaccination. Available at: https://www.who.int/publications/i/item/leave-no-one-behind-guidance-for-planning-and-implementing-catch-up-vaccination
4. Ending Isolation and Precautions for People with COVID-19: Interim Guidance. Available at: https://www.cdc.gov/coronavirus/2019-ncov/hcp/duration-isolation.html

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