Vaccine-induced and Natural Immunity

Which is more effective, immunity that is induced by vaccination or immunity acquired after being infected with Covid-19?

This question is important to raise after Covid-19 has exceeded the positive rate of a million, triggering the government to take the pandemic more seriously. Vaccination is being intensified. The first phase for healthcare workers is under way and will soon be followed by the next group of priority recipients.

The government also imposes public activity restrictions (PPKM), with several provinces applying micro-scale PPKM, which are watched over by the Public Order Agency (Satpol PP), the National Police and even the Indonesian Military. This indicates the government’s greater awareness of mobility restrictions as an important pillar to prevent the spread of infection besides increasing testing and tracing. We certainly should not ignore the criticism of some epidemiologists about the presence of data on millions of affected people that are claimed to be hidden.

The commencement of vaccination has the impact of increasing the self-confidence of the Covid-19 Task Force in dealing with the pandemic. The task force aims to vaccinate 1.3 million healthcare workers, 17.4 million public service workers and 21.5 million senior citizens until the end of April. Thereafter, the general public will get its turn.

It should be appreciated that the task force will raise the vaccination capacity, which is now only around 80,000 injections daily. Around 10,000 health service facilities have already registered and will be supported by vaccine stations, the number of vaccinators will be increased and the working days added to become seven days a week.

This way, the initial vaccination is expected to reach the goal of 40 million recipients until end-April and be carried on to score the 180 million mark. Mass vaccination, as long as there are no unusual contingencies, is expected to develop herd immunity. In theory, herd immunity is achieved when vaccination has involved about 80 percent of the population.

Of course, there are those who doubt or even oppose vaccination for various reasons. For instance, they have read reports describing vaccine recipients who undergo side effects or even pass on. Such news is widely exposed and may disturb the conviction in vaccination.

Also read: Vaccination and Threat of Virus Mutation

We need to remain optimistic. Since it was invented in 1796 by Dr. Edward Jenner, the method of vaccination has been used for 232 years. Vaccination is effective to trigger the body’s immunity response and considerably helps to end or halt the spread of infection. On the other hand, people who are infected but in prime physical condition can produce immunity that will fight the virus.


Plus and minus points of natural immunity

In general, people in prime physical condition (like young athletes keeping discipline in healthy lifestyle and having no history of serious disease) don’t easily get sick due to light infection such as the flu. The flu virus will be easily overwhelmed by the immunity system of their healthy bodies. If they are affected by a virulent and dangerous virus like Covid-19, they are most likely to survive.

In this case, their immunity mechanism is practically ideal. If analyzed, it’s like strong protective umbrella layers comprising components ranging from the skin and mucosae, to lysosomes, phagocytes, immunity cells (“natural-killer” macrophages, neutrophils), complement proteins and interferons that directly connect with immunoglobulins as part of the specific immunity system. All of them are well coordinated. If they are infected, their immunity system promptly identifies the virus, increasing its movement toward the virus (chemotaxis), attaching, devouring and ending in the process of intracellular digestion by the antimicrobial mechanism.

While the immunity system responds by producing body forces that directly eradicate the Covid-19 virus, the body also activates the specific immunity system in which the responsible cells are lymphocyte T and lymphocyte B.

So, natural immunity is formed, meaning the body’s immunity system has identified the virus, its physical form and character, and stored the data in its memory (in this case the plasma cell). If the coronavirus enters again, immunoglobulins are quickly rallied and the body forces are ready to fight and destroy it. This is the working method of natural immunity in the context of non-specific and specific immunity response, which is gained by healthy people directly infected with the virus so that their bodies succeed in normalizing and maintaining the homeostasis of the invasion.

However, in the population of a country the number of people with such prime health condition is small. If only natural immunity is to be relied upon, just a small number of people can enjoy it. Meanwhile, the majority of others face the risk of immunity dysfunction when infected with Covid-19 so that they fail to gain the immunity expected.

Scientifically, it is called an immunity pathological condition, resulting from the failure in synchronizing the causal relation between target cells and mediator cells. The virus is quite smart (through a process of evolution) so that it’s able to encode its certain proteins to oppose the antivirus response of the host, thus optimizing its capacity of invading the host’s cells. The virus can evade the attack of body forces through interferon antagonism so that there’s an extended virus release. Consequently, a malfunction of the body’s defense system occurs (for instance, T-cells commit apoptotic suicide, T-cell receptors malfunction, immunity cells suffer functional exhaustion), viral load increases, cytokines are uncontrollably released so that they cause extensive damage to lung tissues.

Socio-demographically, the population’s majority comprises those in different conditions: people who are just in fairly good health, those affected by diseases that vary in severity, various age groups from infants to the elderly, those living in diverse environmental and other conditions (such as genetic constitutions). Under such varying circumstances it’s difficult to predict who will endure and escape from the invasion of Covid-19 to emerge in good health, who will be free from it but with some damaged vital organs, and who will lose and finally die.

Almost nobody chooses to be exposed in the hope of gaining immunity because the option of being “purposely exposed” is risky. It’s good if one manages to break free and recover, what if the reverse? Most of those infected and surviving the disease acquire several antibodies and immunity cells that can fight infection for a certain period. But their conditions vary because of differences in the number of invading viruses and the state of health. Young and healthy people are more resistant when infected and most likely to recover.

Yet it doesn’t guarantee perfect recovery. One out of every three people recovering from Covid-19 have chronic complaints like fatigue and heart palpitations, as well as lupus-like symptoms (exhaustion, joint pain, rash, fever) for months afterward. These symptoms can affect healthy young people aged below 35 with no history of previous illnesses.

Under such circumstances, in a general population with various health conditions, the situation can be risky if SARS CoV-2 attacks. People who are just in fairly good health but they isolate themselves properly and strictly while treating their other illnesses correctly, can mostly recover by defeating Covid-19. But people with a history of severe diseases like heart disorders, acute respiratory ailments, kidney failure or hypertension can experience different conditions. This is even more so if they live in unhealthy environments, are far from health facilities and economically disadvantaged. The consequence may be fatal, possibly death. A large number of victims have turned out to pass on.

Some of those with one or more serious illnesses have finally survived but one or several vital organs are damaged, failing to function as they did before Covid-19 infection. The population’s majority is in such a risky situation. This majority is generally under the threat of virus infection, at the same time with the potential to become an agent spreading the disease. That’s why vaccination is very important.


Efficiency of vaccine-induced immunity

As the greater part of the population is so vulnerable, vaccination is intended to protect the majority with such diverse health conditions. It’s also very economical to control the highly infectious Covid-19.

However expensive vaccines are, it’s still far less costly compared with the treatment of a Covid-19 patient, which may amount to hundreds of millions of rupiah. The proper development of vaccines is designed to imitate the natural protection of a healthy body. The body’s immunity system is expected to work very well so that it can identify the virus and then respond to it by producing antibodies and body forces that will neutralize or eradicate the virus. Vaccine development is conducted in a highly measured and controlled way so that generally they can offer efficacy, safety and minimum side effects that can be tolerated. By injecting vaccines derived from weakened or dead viruses (a method of vaccine production), the body is trained to identify the form of the virus so as to induce immunity response.

Another approach applies a more advanced technique. This type of vaccine emphasizes its operation at the genetic level, by putting instruction into the DNA or RNA or using a benign virus (as a virus vector) to send antigens (spike proteins that induce protective immunity response) directly to cells in the body’s immunity system. It is expected to trigger immunity response. This vaccination will produce spike proteins of the coronavirus that enters the body. The radar of the body’s defense system will identify the form of the spike proteins that are seen as the genuine virus. So, the control center of the defense system directly produces immunoglobulins and multiplies body forces while ordering them to attack and destroy the spike proteins, which are taken as the real virus.

This is what happens, with the defense system being trained to identify and eradicate the virus. If one day the real coronavirus does enter the body, the memory of the body’s defense system is already aware, familiar with it and promptly produces immunoglobulins and sends body forces to intercept. The virus is thus destroyed by the well-armed body forces. Besides, there’s still another approach, such as protein-based vaccines with the same end result: inducing immunity response to prevent infection.

Vaccination is designed to protect the population’s majority with highly diverse conditions. With the range of efficacy of the five vaccines already authorized by the Food and Drug Monitoring Agency (BPOM) of around 60-94.5 percent, they are medically believed to be capable of inducing sufficient immunity response among the majority of people, at the same time curbing the spread of the disease. Is the immunity gained from vaccination better than natural immunity acquired by people recovering from infection?

So far there have been no reports of its study results. But by referring to vaccine development for several pathogens like pneumococcus that attacks the respiratory tract, vaccination has proven to produce better immunity than that resulting from direct exposure. In the case of Covid-19, initial data at least give such an indication. Volunteers injected with Moderna vaccine doses have a lot more antibodies in their blood (a yardstick for immunity response) than those without vaccination after recovering from infection.

In the vaccination scenario, everybody will receive the same dose. This dose has been properly designed in order to bring about immunity response among members of the majority with different health conditions. It is aimed at producing herd immunity so that infection can be minimized. It means that when the greater part of the population is immune, somebody affected by Covid-19 cannot spread the disease. It’s obviously unlike natural immunity, which has to go through natural infection to achieve herd immunity, but the minimum rate of mortality is 1 percent, even more, among all people in the community. It’s indeed unacceptable to common sense.


Minimum risk involved

To date, Covid-19 vaccination has only given rise to minimum risk. There are indeed reports that some vaccine recipients have had side effects, even others have died. But those who died were in fact because of their previous severe underlying diseases. The number of people with side effects is actually very small compared with the entire total of vaccine recipients all over the world. The side effects due to vaccinations are far less than the effects arising from direct exposure without vaccination.

People who recover from Covid-19 infection and therefore have gained immunity, if later vaccinated, is there any benefit? Hypothetically it remains beneficial because their natural immunity response will increase after vaccination. Vaccination can be a booster of natural immunity after getting free from infection. With reference to vaccine clinical trials, 10 percent of participants turned out to have been exposed to Covid-19 without their being aware of it and their immunity response is being analyzed. In this way, in general this vaccination is safe and its risk potential is minimum. That is vaccination, a scientific and wise method of acquiring efficient and effective herd immunity.


Djoko Santoso, Professor of Medicine, Airlangga University; Chairman of Health Agency Executive Board, Indonesian Ulema Council of East Java; Survivor of Covid-19.

(This article was translated by Aris Prawira).