Do we need to vaccinate every child against COVID-19?

Nearing the two-year mark since its emergence, SARS-CoV-2 has been associated with less than 0.1% mortality in the 470 million population of children in India. Most children who contract the virus suffer from mild symptoms or may even be asymptomatic, usually recovering without the aid of COVID-specific drug therapy. The interpretation of national and international data from the first two waves of the viral infection shows that approximately 2-3% of those falling in the age bracket of 5 to 12 years are expected to require hospitalization by the time we are hit with the next one. According to ongoing research and guidelines, drugs commonly used in the treatment of severe infections in children under the age of 18 play little to no role. Health professionals have taken on the role of mixologists, tirelessly searching for newer medications as well as the best cocktails and combinations such as Baricitinib with Remdesivir and REGEN-COV that can be used in the treatment of this specific infection. However, these drugs require more extensive research and time to prove their safety – time that we may not have.

It is critical to remember that a child’s immune response to the virus differs from that of an adult. Multiple hypotheses have been proposed, including lower levels of ACE2 receptors in the nasal epithelium, where the virus may attach, and partial protection due to more frequent exposure to 5 other coronaviruses in the same age group. No study dispels the fact that children are immune to the disease and much larger studies are needed to understand the duration and quality of their immune responses as well as the transmissibility. It must also be kept in mind that while they may have lesser chances of contracting the virus, their immune response would be much more intimidating than that of an adult’s. Multi-system inflammatory syndrome in children is a dreaded complication of the viral infection, usually reported 2-6 weeks after the peak of COVID-19 infections in the affected population. Although complications of the virus attack do not usually reflect on the lungs of the child, steps need to be taken to prepare for appropriate paediatric equipment to sustain them in case of unexpected events in the tides created by variants of the virus in the foreseeable future.

The fourth national blood serum survey which tests for antibodies included around 8,700 children aged 6-17 years for the first time and half of them were seropositive; albeit, their antibody titres were low. Although they may be important in judging the severity of the infection, antibody quantification is not of much use in explaining and interpreting the risk of contracting the disease as every individual is unique and would therefore need a unique level of neutralizing antibodies to prevent infection in his or her body. Earlier this year, repeated claims of herd immunity have been confidently made, only proven to be terribly wrong by the catastrophic events which took place later. It is possible that these erroneous predictions were made on the basis of misinterpreted antibody surveys. The pandemic raged through multiple countries across the world even when a seropositivity rate of 76% was reported in the population – for example, Brazil. This only goes to show that with the emergence of new variants, protection slips. In addition, herd immunity is an attribute of the population and is not applicable to individuals. A high-level immune individual in any stable population group blocks transmission of the virus to the minority who are not immune. That protective cordon is no longer available when a non-immune person moves to another part of the city or country where the population has not yet reached the herd immunity threshold and the virus is in active rampage.

As we grow, the number of T-cells in our body dwindles – meaning it becomes more and more difficult to generate robust immune responses to new infections later in life.  Neither children nor adults had memory T-cells for COVID-19 at the start of the pandemic, since no one had been exposed to the virus yet. But because adults and the geriatric population have significantly fewer amounts of naive T-cells, it takes a longer time for their innate immune system to respond, which could be the cause of more severe infection seen in them. While some scientists have been working on developing a cure for the disease which the virus has already caused, some have been working towards creating molecules which may help develop memory to equip the immune system to reject unwanted foreign particles as soon as they enter the body. Multiple competitors in vaccine development have delved into researching new and exciting ways to do the same. It would be proving partial to pick even just a few from the large pool of already available ones, but a particularly interesting group of vaccines look promising – mRNA vaccines. In a reasonably sized clinical trial, the mRNA-1273 vaccine showed 94.1% efficacy at preventing COVID-19 illness, including severe disease. Simply put, COVID-19 mRNA vaccines give instructions for our cells to make a harmless piece of what is called the spike protein, which is found on the surface of the virus that causes COVID-19 – thereby making it simpler to initiate a bodily response but desisting the disease process. mRNA vaccines have been studied before for flu, Zika, rabies, and cytomegalovirus, and future mRNA vaccine technology may even allow for one vaccine to provide protection for multiple diseases, thus decreasing the number of shots needed for protection against common vaccine-preventable diseases. But let’s not get ahead of ourselves...

Mass vaccination for children, while an ambitious public health program with the best of intentions may be problematic and challenging, especially in developing countries where the number of inhabitants exceeds healthcare resources and manpower by a large margin. As seen in the recent past, maintenance of social distancing was a herculean task despite scheduled appointments for the jab. Imagining the crowd if an average of even just two people accompanied the child for vaccination makes it impossible to expect appropriate distancing and may even increase the chance that these designated centres would become a breeding ground for the virus to thrive. Instead, cocooning for immunosuppressed or chronically ill children can be implemented, like it was in the control of pertussis; in which those who come in close contact with or have family members who are suffering from the disease can be vaccinated on an emergency/urgency basis. Ring vaccination can also be enforced as opposed to mass vaccination, akin to that which was done for small pox and more recently, Ebola. COVID-19 vaccination can also be integrated with the child immunization schedule – for example, the Intensified Mission Indradhanush in our country. Keeping in view the drop in conduct of essential services worldwide as per recent reports, this could ensure more coverage and grip over data regarding those who have been overlooked.

Ultimately, reinforcements must be made to design a vaccination program in such a way that the sole aim is to improve a child’s chance at life despite the country and situation in which they were born without encouraging the spread of the disease by using the time between roll-out of the vaccine and immunization to step up paediatric specific resources and ceasefire any civil conflict to allow this to happen. Similar to vaccines against other viruses, the youngest among us may actually be the ones to show the best responses that will provide lifelong protection. This jives well with the immune system in theory – ‘survive, and then remember how to survive again.’