Position Statement No. 11: Understanding the vaccine – the individual perspective

“Without vaccination, after contracting COVID-19, out of a group of one million people, thirty thousand will not survive. This is approximately the risk of death due to the disease in Poland” – scientists from the COVID-19 Advisory Team to the President of the Polish Academy of Sciences wrote in a position paper dated 10 February.

The COVID-19 vaccination campaign is underway. It is the largest undertaking of this kind the history of medicine has seen in recent decades. Its outcome will depend on many factors. In this statement, we present the key factors underpinning the success of this complex operation. We also describe what to consider before getting vaccinated. In the Advisory Team’s next position statement, in turn, we will focus on what vaccination means from a societal perspective.

The current choice is between vaccine and infection. As each of us makes our personal decision to be vaccinated or not, the following comparison may be helpful: if we take a group of one million people, less than three of them will have a severe anaphylactic reaction after vaccination. This does not mean death, only a need for immediate medical attention. Without vaccination, after contracting COVID-19, out of a group of one million people, thirty thousand will not survive. This is the approximate risk of death due to the disease in Poland. This varies by age and body weight, but even in the case of teenagers hospitalized with COVID-19, the risk of death is ten times higher than in the case of hospitalization for influenza. The long-term effects of SARS-CoV-2 virus infection on the whole body are also unknown. In contrast, no lasting complications have been identified following vaccination. Let us remember, every dose of vaccine given brings us closer to a return to pre-pandemic normality.

Components of the vaccination process

a) The vaccine and its availability

One essential element of the vaccination process is having an effective, safe, and accessible vaccine. A primary role in this regard is played by manufacturers, clinical trial sites, agencies that authorize vaccines for use, administrators who ensure the logistics and organization of vaccine distribution, and the vaccination centers themselves. The speed at which COVID-19 vaccines have been developed and the first batches manufactured is impressive. It is also crucial for the success of vaccination that the vaccine should be available to everyone. Essential in this context are smooth negotiations with the manufacturer (mainly at European Union level), the organization of the national-level vaccination system, including the storage and transport of vaccines at appropriate temperatures, the planning of vaccination appointments, ensuring safety measures at vaccination centers, and the appropriate documentation and monitoring of vaccinations and their effectiveness. With modern technology facilitating such organizational processes, it is hoped that this highly complex logistics will improve month by month.

b) Medical personnel

Another, equally important element of the vaccination process is having professional medical personnel to screen individuals for vaccination and administer the vaccine, abiding by the indications and contraindications and ensuring maximum effectiveness and complete safety at the vaccination center. The decision to vaccinate must be made on an individual and person-focused basis, so as to take into account any potential coexisting medical conditions and contraindications. It should be emphasized that both the performance and non-performance of any medical procedure involve a certain degree of risk. The individual decision to vaccinate, not to vaccinate or, for example, to postpone vaccination results from risk analysis and comparison, to be carried out jointly by the person to be vaccinated and the physician, so that an optimal course of action can be identified for each of us.

c) The vaccinated person

The third element in a successful vaccination process is the vaccinated person himself or herself, who should be prepared to receive the vaccine. In medical terms, it is our immune cells that must effectively utilize the vaccine antigen or the information stored in the mRNA to produce immunity. This process proceeds slightly differently in each of us, and each of us reacts differently to the vaccine. However, it has to be taken into account that the development of post-vaccinal immunity is a process that lasts from a few days to two weeks, during which the person is still sensitive to the infection. In the case of currently available vaccines, the immune system only begins to fully protect us 7 to 14 days after the second dose. Therefore, do not succumb to a false sense of security and continue to scrupulously observe the rules: wear a mask, keep your distance, and wash your hands frequently. We now know that getting vaccinated protects us from infection with the SARS-CoV-2 virus and the dangerous consequences of the disease. However, we do not yet know whether vaccination protects us from infecting others. Therefore, as long as we do not know for sure, or until the pandemic subsides, it is important to scrupulously observe the above-mentioned rules even after getting vaccinated, for the sake of others.

What should one know before getting vaccinated?

The effectiveness of vaccination can be evaluated by laboratory means, clinically and epidemiologically. It is important to remember that SARS-CoV-2 infections may proceed completely asymptomatically, or may involve symptoms of COVID-19. In turn, symptomatic infections can be mild or severe, and can even lead to death. The true measure of the effectiveness of vaccination, regardless of the type of vaccine, is decreased risk of contracting the disease. Clinical trials compare the incidence of COVID-19 in participants actually vaccinated versus those who received a placebo and the degree of reduction in this risk achieved by the vaccine is calculated. The risk of death from SARS-CoV-2 infection in those receiving the vaccine and placebo is also compared. The effect of vaccines on asymptomatic infections is the most difficult to measure – in this respect we are still awaiting the results of clinical trials.

The outcome of vaccination depends, among other things, on the age and health status of the vaccinated person and the type of vaccine used. Vaccination does not eliminate the risk of contracting the disease completely, but only reduces it. Even the best available vaccines provide approx. 99% protection against the disease. The available vaccines used to protect us against respiratory infections (e.g. against influenza), for instance, have an effectiveness of 50-70%. COVID-19 vaccines containing mRNA have been shown to reduce the risk of disease by around 95% overall, across all age groups. Another COVID-19 vaccine approved for use, containing a viral vector, has an efficacy of 60-70%; as we are still awaiting the results of clinical trials on its use in people over 55 years of age, it is being offered to young adults exceptionally out of turn under the general strategy that older people have priority. Such individuals therefore face a choice: to obtain a risk reduction of around two-thirds now, or to wait a few more months until more effective preparations become available. It should be remembered that in the case of vaccines, 40% is taken as the minimum acceptable risk reduction. Any other preventative medical intervention that reduced the risk of, for example, heart attack or diabetes to a similar degree would be considered valuable and worth considering.

The effectiveness of vaccination, even with the most effective preparations, may be lower in immunocompromised individuals, those undergoing chemotherapy, having undergone transplantation, or infected with HIV. This does not mean, however, that such people should not be vaccinated. Clear-cut data on the effectiveness of the vaccine for these groups will still take a while to come in. Things are similar in the case of pregnant women. It should be emphasized, however, that currently available vaccines against COVID-19 do not contain “live” viruses, which might multiply in the body in the case of weakened immunity or, for example, penetrate through a pregnant woman’s placenta to the fetus or infect an infant via breast milk.

With the advent of vaccines, some people have called their safety into question. These doubts are not grounded in reality. We would all feel more comfortable with years of data on the efficacy and safety of particular SARS-CoV-2 vaccines. However, we do not have that time, when there are huge numbers of cases and as many people as possible need to be vaccinated urgently. Vaccination decisions – both strategic decisions and personal ones – therefore have to be made without having answers to all the questions that present themselves, including how long the protection will last and whether the vaccine will protect us against emerging new variants of the virus.

Vaccination is intended to provoke our immune system to work against a specific threat. That is why, after vaccination, we might feel pain, notice swelling or redness in the place where the vaccine is administered, and sometimes enlargement of the lymph nodes on the side of the vaccination. Some people may experience fever, muscle aches, a feeling of drowsiness or fatigue, depressed mood or even diarrhea or vomiting. We may feel similar to having the flu and fear that we have been attacked by the disease instead of being protected. However, this is a symptom indicating that our immune system has been forced to work intensively – a state of inflammation develops, cytokines are released, and immune cells are stimulated, learning to recognize virus antigens. These symptoms are expected and are usually mild, resolving within hours or days without intervention. The severity of post-vaccination symptoms tends to be slightly higher in young people than in seniors, and is more frequent and more severe after the second dose of the vaccine. Some of these reactions are not related to the vaccine itself – this is evidenced by the fact that in clinical trials such side effects were also experienced by people receiving a placebo. Some people may not experience any symptoms, even such mild ones as temporary discomfort, but this is not a sign of the ineffectiveness of the vaccination – rather, each of us reacts to vaccination somewhat differently.

Potentially the most dangerous reaction to vaccination is a severe anaphylactic reaction to the vaccine components. Currently available mRNA vaccines do not contain the typical allergens – latex, egg white or yeast. Anaphylactic reactions occur rapidly (within a few minutes or a quarter of an hour) or not at all, making it essential to wait 15-30 minutes after vaccination under the supervision of medical personnel. It is important to stress that the risk of a severe anaphylactic reaction after vaccination is estimated at around 3 per million vaccinated persons, and it is obligatory for every vaccination center to be prepared, equipped, and trained to give immediate assistance in the event of such a reaction.

What next?

The first objective of the vaccination campaign is to reduce the number of illnesses, hospitalizations and deaths, and to free up the capacities of the healthcare system.
Therefore, medical personnel and people who most often need a hospital bed and for whom the disease often has a tragic outcome – seniors – are getting vaccinated first. This measure alone should contribute to curbing the effects of the pandemic and allow at least a partial return to normality.

The second objective is to bring the number of new infections and illnesses down to a minimum. To achieve this, vaccinations will gradually be given to younger and younger people who are less likely to be severely affected by the disease.

The third goal, the complete eradication of SARS-CoV-2 from our environment, will probably not be attainable, because the virus has established reservoirs in the animal world – it is found in cats, mink and even deer. Full control of the spread of the virus in these reservoirs is unachievable. However, the fewer viruses circulating among humans, the lower the risk of new vaccine-resistant variants emerging.

About the team

The Interdisciplinary COVID-19 Advisory Team to the President of the Polish Academy of Sciences was set up on 30 June 2020. The team is chaired by Prof. Jerzy Duszyński, President of the PAS, with Prof. Krzysztof Pyrć (Jagiellonian University) as deputy chair and Dr. Anna Plater-Zyberk (Polish Academy of Sciences) as its secretary.

Other members of the team are:
Dr. Aneta Afelt (University of Warsaw)
Prof. Małgorzata Kossowska (Jagiellonian University)
Prof. Radosław Owczuk, MD (Medical University of Gdańsk)
Dr. Anna Ochab-Marcinek (PAS Institute of Physical Chemistry)
Dr. Wojciech Paczos (PAS Institute of Economics)
Dr. Magdalena Rosińska, MD (National Institute for Public Health – National Hygiene Institute, Warsaw)
Prof. Andrzej Rychard (PAS Institute of Philosophy and Sociology)
Dr. Tomasz Smiatacz, MD (Medical University of Gdańsk)