COVID-19: Importance of post-vaccination surveillance and adverse events monitoring

Published On: July 21, 2021 02:26 PM NPT By: Rajshree Thapa, Kiran Bam and Satish Raj Pandey

Monitoring and surveillance will enable early detection and investigation into adverse events following immunization and adverse events of special interest. 

With the rapid vaccine coverage of COVID-19 vaccines mostly in high-income countries, many low- and middle-income countries are still facing critical shortage of vaccines, while they face the scourge of new waves in the wake of the Delta variant spread. As of July 18, 2021, around 3.66 billion doses of vaccines have been administered with 26.3% of world population fully vaccinated. However, there is disproportionate vaccine distribution with high-income countries administering 30 times faster than low-income countries. Only one percent of the low-income countries’ population has received at least one dose. Most low- and middle-income countries still lag behind in vaccination coverage; the prime reason for which, surprisingly, is not the lack of funds but the shortages of vaccines in the global market exacerbated by excessive ordering and hoarding by some rich countries. As Nepal is slowly on the path of accelerating the COVID-19 vaccination, through doses donated or procured, more people will be getting their first jabs in the very near future.

The pandemic engulfed Nepal with a rapid spike of cases during the recent second wave. The devastation was widespread and the urgency for COVID-19 vaccinesbecame even more evident.The scarcity of the vaccines meant that while some people started queuing up for the first jab, a large proportion was still in despair. The vaccine distribution was initially targeted at the older population (mainly 65 years and above)as well as some ‘frontline’ workers. The remaining population had no optionbut to anxiously wait for their turn under the uncertainties linked to the global vaccine shortages. As of July 18, 2021, since months into the COVID-19 vaccination campaign, only 3.06 million people (around16% of population above 15 years) had received at least one dose and only 3.7% of total population (1.1million) or 5.8% of population above 15 years had been fully vaccinated in Nepal. Although, the most recent eligibility is 18 years and above for Nepal, few countries have already started inoculating children from 12 to 15 years. The age criteria for Nepal may be expanded as more vaccines and data on efficacy among the younger population becomes widely available.

The scenario of vaccine availability in Nepal is showing positive hints of turning a corner. Recently, Nepal reportedly procured around 4 million doses  of Sinopharm vaccines through the Chinese Government. Through generosity shown by the US Government, Nepal was able to securea gift of 1.5 million Johnson & Johnson. Per the recent news, Nepal has already received 6.58 million doses of  vaccines and another 6.4. million doses have been confirmed and the process is underway to bring these vaccines to Nepal. These received and in process of receipt adds up to 12.98 million doses of vaccine which is sufficient to fully vaccinate around 34% of 19.11million population in the age group of 15 years and above assuming everyone will be requiring double dose (the amount of confirmed single dose –Johnson & Johnson vaccine is quite low)  and Nepal will maintain low vaccine wastage rate (1%). This figure also includes 1.5million people awaiting their second dose.The recent news onNepal expecting1.6 million doses of AstraZeneca from the Government of Japan is somewhat relieving to those eagerly waiting for their full vaccination coverage.

With the encouraging vaccine availability in the country, one of the major concerns is the equitable distribution of the vaccines along with the monitoring and surveillance of the vaccinated individuals. This is critical given the circulation/use of the range of vaccines in the country. The current policy of the Government of Nepal appears to make any approved vaccines available for as many people as possible.  When the country is struggling with glaring vaccine shortages, it is understandable that the country will strive towards getting the population vaccinated to enable some level of immune response rather than leave the population vulnerable. As the speed of vaccination picks up, it should be backed with robust post vaccination monitoring and surveillance. This is not only important to enable monitoring of the adverse events but also to assess if the vaccine is producing the intended immune response in Nepal as they are rolled out in real-life settings.

Of concern is the varying levels of immunity produced by the vaccines while different SARS-COV-2 variants are at play. There have been instances where certain countries have had to make difficult choices to drop available vaccines due to the lower protection the vaccines accorded under the given context. For example, in South Africa, AstraZeneca was found to be less effective against the Beta variant. The country decided to stop using these vaccines and switched to other options. All low-income countries do not have this luxury. They either can’t afford to switch to other vaccines easily or do not have the necessary resources to adequately carry out genomic sequencing so that they can ascertain the predominant variant in the country at any given time.  In those countries, local capacity for genome sequencing remains very limited. In the same vein, the Government of Nepal, so far, has largely relied on sending samples out, hampering regular monitoring of the prevalent variants. While there are indications that the country will be undertaking in-country genomic sequencing in the near future, the choice of vaccines will still be limited by the availability of adequate vaccines.

It is very well established that all vaccines come with some side effects. The side effects may be  local reaction (redness, swelling and pain at injection site), systemic reaction (fever, fatigue, headaches,  chills,  vomiting, diarrhoea, new or worsening joint pain), unsolicited adverse effects such as lymphadenopathy and even rare life-threatening adverse conditions. Our  surveillance systems need to be prepared for identifying and responding to both adverse events following immunization (AEFIs) and adverse events of special interest (AESIs) or any other events of public concern following immunization. AEFIs are the unintended or unfavourable medical events or reactions following  COVID-19 vaccination but may or may not have  causal relationship with the inoculated vaccines.Similarly, AESI are the  “pre-identified predefined medically-significant event that has the potential to be causally associated with a vaccine product that needs to be carefully monitored and confirmed by further specific studies”.These adverse events may be related to number of conditions such as vaccine product-related reaction precipitated by a vaccine due to one or more of the inherent properties of the vaccine product. The chances of such conditions are extremely low in World Health Organization (WHO) approved vaccines. The other condition is the vaccine quality defect-related reaction: those AEFI that are triggered by the quality defects of vaccine products including administration device such as  defect in syringes.The other AEFI are due to the inappropriate vaccine handling, prescribing or administration termed as immunization error-related reaction which is largely preventable. The other events could be due to the anxiety and/or coincidental events. Majority of these side-effects are mild and due to stringent regulatory mechanisms, severe conditions resulting from approved vaccines administration, although possible, are rare.  Blood clotting episodes following AstraZeneca/Oxford application or rare occurrence of Guillain-Barre syndrome (GBS), a neurological condition linked to Johnson &Johnson have been surfacing, recorded in countries with strong adverse events monitoring systems in place. As these events have been rather rare and, at times, confined mostly to certain age groups, the overall benefits of vaccination still exceptionally outweigh these risks.

Monitoring and surveillance will enable early detection, investigation and adverse events following immunization and adverse events of special interest. COVID-19 immunization data relies on routine monitoring (facility-based information), periodic surveys (household level) and surveillance systems (monitor and manage cases of vaccine-preventable diseases). Case-based adverse events reporting, with attention to the type or brand name of the vaccine and the manufacturer along with details such as batch numbers and documentation of dates, pregnancy and lactation status in women and the use of concomitant medications is important.  Both active and passive surveillance through engagement of different stakeholders can produce fast and reliable information on any severe adverse events. Pharmacovigilance and post-vaccination surveillance are necessary while vaccination is being rolled out. It is critical to monitor any adverse events resulting from these mass vaccinations being carried out in our context.

Nepal has a sound regular immunization program and the vaccination related expertise at the centre and the periphery is quite rich. The national immunization committee comprises very experienced experts who work as the think tank to conceptualize and roll out national immunization programs. The challenges that COVID-19 vaccination poses are mainly two-fold; firstly, this new vaccination for a new disease, and secondly, the vaccination needs to cover populations of all age groups (after vaccines are eventually approved for children too) which means that it is rolled out at an unprecedented scale. No country has the experience in rolling out vaccination at such a large scale to protect all populations at one go. Therefore, a continuous vigilance is mandatory following the vaccination period to identify and assess any reported adverse events specifically, events of special interest.Further, post vaccination monitoring will generate knowledge on the effectiveness of the vaccines across sub-population, geographic locations, and varying health-care settings.

Keeping the above challenges in mind, Nepal needs to put a sound system in place in order to ensure a close monitoring of the adverse events resulting from COVID-19 vaccination. It is very possible that as the vaccination is scaled up in Nepal, the roll out will have to be increasingly done through public and private collaboration and the role of the local bodies will also become very important. A more inclusive and decentralized delivery mechanism, while ideal, also comes with its own challenges. Efforts early on, therefore, should be focused on harmonization of information and data collection so that reporting and monitoring processes are properly streamlined. Proper information gathering from the clients covered by vaccination facilitates better follow up. Identifying data needs and strengthening information systems to monitor progress with COVID-19 vaccination is essential to take corrective action where needed. Strengthening the digital systems and online platforms wherever feasible, should be promoted for registration, update vaccination records and logistics management.

The Online COVID-19 vaccine registration form initiated by the Ministry of Health and Population is an excellent platform for gathering client information.Use of online apps to record self-reported side effects within 8 days of immunization has been reported in a recent study in the UK.  Such practice can be replicated through upgrading of the existing app of the Ministry of Health and Population such as Hamro Swasthya or any other similar platforms. Now that the country has some experience already in rolling out the COVID-19 vaccines, this is the best time to assess if the information collected from the clients for vaccination is adequate for proper and timely follow up. These forms should include, at a minimum, information about the vaccination status and the brand of vaccines used, age, sex, occupation, any pre-existing co-morbidities, and geographical coverage to enable population-wise safety and effectiveness analysis.These records should be built, where applicable, within the routine health data system. It will also be useful to link the vaccination form and its information to generate a quick response (QR)-code based vaccination certificate which can be used by the fully vaccinated population as ‘green passes’ for the ease of travel or be engaged in public events, visit restaurants and participate in other social activities.

Proper education/counselling at the time of the vaccination will enable the clients to report any adverse events that they might face immediately after vaccination or within a stipulated period. This can be facilitated by active follow-ups of the vaccinated population which needs to be done in a practical manner so that those that are not self-reported can also be covered. Follow-up of specific vaccinated cohorts for at least a year will enable monitoring of vaccine effectiveness. Sentinel sites specifically managing high cases of COVID-19 can follow up certain cohorts for at least a year to generate data on effectiveness of vaccines or any severe adverse events following immunization. This will necessitate strengthening laboratory facilities and experienced well-qualified staff to identify and report high quality data on adverse effects in these sentinel sites.The hospital records need to be updated. This will also enable analysis of COVID-19 breakthrough cases, hospitalization, and deaths among the vaccinated populations.

There is some international evidence on this front but having information to analyse from within the country is the best way to evaluate the situation for timely decision making. This will also enable us to evaluate if vaccines have been able to have a positive impact on hospitalization and deaths resulting from COVID-19. Post-vaccination surveillance and monitoring at strategic locations such as airports and other exit points may be useful as the current vaccination also targets the migrant population. Vaccine effectiveness studies/surveys will enable tracking those not in routine health systems. Further, a continuous vigil for strict adherence with the standard protocols for storage, handling, supply distribution, transportation and logistics procedures and practices is imperative to achieve full potency of vaccines.

Risk and vaccine communication remain a priority and Nepal has recently endorsed directives on risk communication and community engagement.Vaccine communication should focus on educating and informing at the community-level on the availability and effectiveness of the vaccines and designing strategies to facilitate access tothose vaccines. Further such messaging should address the vaccine hesitancy and debunking the myths associated with the vaccines. This also provides a golden opportunity to educate the clients about self-reporting any side effects that they might experience. Simultaneously, there is a need for continuous focus on adherence to public health measures, SMS (social/physical distancing, mask use,sanitizing hands) irrespective of COVID-19 vaccination status. Israel and UKare examples where cases are surging despite their extremely high vaccination status.  The enforcing and reinforcing of public health measures along with post vaccination surveillance and monitoring remains the critical priority as the country gradually rolls out the vaccination with the aim to reach at least 72 %of its population. In case of emergence of other more transmissible variants, this threshold might be even higher.

 (The authors are public health professionals with experience of working in Nepal’s health sector.)

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