As mass vaccination against the coronavirus that causes Covid-19 continues around the world, new drugs, new questions about them, and new updated data about how different categories of people tolerate vaccination, the efficacy of vaccines, the side effects seen, the duration of immunity developed, and so on, are emerging.
There is so much information on the Internet that it is very difficult to navigate. It is virtually impossible for a person without specialized training to evaluate the trustworthiness of a particular source. Even the most authoritative publications sometimes contradict each other because doctors and scientists from around the world have not yet reached a consensus on some issues.
The Russian BBC service continues to answer the most frequently asked questions about vaccination. The latest update includes information on how long a break is allowed between two vaccinations, why there are two injections in principle, whether it is possible to mix different vaccines if necessary, and how reliable protection against the virus can be provided by the first of the two doses of vaccine required.
Vaccination is the most reliable way to protect yourself and your loved ones from severe cases of Covid-19. Considering the dynamics of the virus spread, sooner or later everyone will catch the infection, so it’s better to prepare your body in advance and provide yourself with even partial immune protection (more about it here).
It is known that the coronavirus is particularly dangerous for people who already have a chronic disease: they may develop an autoimmune reaction (when the body starts attacking its own healthy cells instead of the foreign virus) and there is a high risk of developing complications.
For this reason, it is strongly recommended that people with lung or bronchial problems, cardiovascular disease, and diabetes get vaccinated as soon as possible, but it is imperative that you consult your doctor first.
Contrary to popular belief, it is impossible to get sick from a vaccine injection: it does not contain viral particles capable of replication. Depending on the type of vaccine, it contains either an inactivated virus (the most traditional vaccination technology), a fragment of its genetic code (vector vaccines), or artificially produced proteins (peptide vaccines). In any case, they are not capable of penetrating cells and provoking the development of an infection.
People who claim to have become ill as a result of vaccination could have been infected during the vaccination process (in transit, in line for vaccination, etc.), but not as a result of vaccine administration.
It is important to remember that even healthy people who have recovered from Covid-19 can carry and spread the virus. Therefore, precautions such as wearing a mask and social distancing should be followed not only before and during vaccination, but also after vaccination.
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Like any other medication, coronavirus vaccines have a list of contraindications where administration of the medication may cause more harm than benefit. Each specific vaccine has its own list, but at present almost nowhere are minors vaccinated (except in the USA, where Pfizer has allowed teenagers older than 12 years to be vaccinated), as well as pregnant and breastfeeding women (according to the opinion of many scientists, this is a big mistake – pregnant women should urgently be included in the high-risk group) and people prone to severe allergic reactions. It is also possible to have an individual intolerance to certain components of the vaccine, but this is extremely rare. In such cases, another medication will be recommended.
If you are in Russia, you are most likely to be offered a shot of “Sputnik V,” which its developers call “the world’s first registered coronavirus vaccine.” The medication’s labeling states that it should be used “with caution in patients with chronic liver or kidney disease, diabetes, severe blood disorders, epilepsy, stroke or other central nervous system disorders, history of myocardial infarction, ischemic heart disease, primary or secondary immune deficiencies, autoimmune diseases, lung disease, asthma, and COPD (chronic obstructive pulmonary disease).” Return to the beginning.
Short answer: because no vaccine has been tested on them. The pandemic of the new coronavirus caught the world by surprise, so all vaccines were developed and tested in an emergency, accelerated mode. In order to get vaccinations out as quickly as possible, developers had to take huge risks and cut corners on the most stringent requirements. Some of them started mass production even before the first results of human clinical trials were available. In the end, however, the journey from the selection of experimental laboratory samples to the start of vaccination, which can normally take decades, was completed in less than a year. Because children are much more likely to tolerate the infection and have a much lower risk of serious consequences if infected (and because it is much more difficult to recruit minors as volunteers), they were not initially included in clinical trials. For the same reason, vaccines licensed for adults were not initially given to people over the age of 60 or 65. In the first group of clinical trial participants, there were either no volunteers or not enough volunteers in this age group, so developers could not draw conclusions about how effective and safe the vaccine would be for them. In the elderly, Covid-19 often occurs in a severe form, so they were included in the studies immediately after they were conducted in healthier and younger adults. Currently, all major vaccines except AstraZeneca’s (in some countries) are used to vaccinate the elderly. Now several already approved coronavirus vaccines are being actively tested on minors. The head of Pfizer (its vaccine was urgently approved by the WHO on December 31, 2020) stated that the first vaccine for teenagers aged 12-16 will be registered in the fall, but in the USA the vaccination of teenagers has already begun. Vaccines for even younger children should be available by the end of the year. Go back to the beginning.
As much as scientists can be confident in the safety of the vaccine. On the one hand, the third, crucial phase of clinical trials for any vaccine, even in adults, has not yet been fully completed. All reported results, including data on the efficacy of a particular drug, are preliminary. On the other hand, there is no more reliable evidence of the safety of a particular drug than active global mass vaccination. In total, nearly 1 billion people have received at least one dose of the vaccine (of which nearly 500 million have been fully vaccinated), so scientists have no doubt that none of the widely used vaccines pose a threat. These include Covishield (AstraZeneca), Janssen (Johnson & Johnson), Moderna, Comirnaty (Pfizer/BioNTech), two Chinese vaccines (BBIBP-CorV and CoronaVac), and the Russian “Sputnik V”. However, only the first six have been officially approved by the WHO. “Sputnik” is still under review. The likelihood of serious side effects that can threaten health or even life (such as sudden thrombosis) cannot be completely ruled out. However, they are so individual that they are impossible to predict, and they are so rare (see below) that the benefits of vaccination far outweigh the potential risks. Go back to the beginning.
There are some, but – if we do not consider contraindications – their number is relatively small. Vaccination is not recommended for people with any chronic disease in exacerbation (including cancer patients), or any other acute infection in active form (elevated temperature – a sufficient but not mandatory sign of inflammation in the body). Taking certain hormone medications will reduce the effectiveness of the vaccine, but will not prevent it. If you feel unwell for any reason the day before or a few days before the vaccination, it is better to postpone the vaccination. In case of exacerbation of chronic diseases, vaccination is recommended at least two weeks after recovery or remission. If possible, it is better to wait a month. It is also better to consult your physician on this matter. If we are talking about mild forms of respiratory viral infections, such as the flu, it is possible to vaccinate earlier – shortly after the patient’s temperature has naturally normalized and they have stopped taking the pills. Do not listen to people who advise you to take medication before or immediately after an injection to reduce the risk of side effects. Doctors say such advice is not only useless, but probably harmful. In extreme cases, if you are very nervous before the vaccination, you can take a mild sedative. Go back to the beginning.
Independent experts from different countries agree that the best vaccine available today is the one that is personally accessible to you. In other words, any of the drugs that are licensed for use in your region and are currently available. The only exception to this general rule is if you have contraindications to a particular vaccine. In this case, it really makes sense to get vaccinated with another safe drug if it is available, or to wait until it becomes available. Important note: If you have any doubts about this (or any other vaccine issue), it is better not to rely on your own opinion or the advice of relatives, friends, or acquaintances – even those with medical training. Since the list of available vaccines varies greatly from region to region, and each drug has its own contraindications (not to mention possible individual intolerances), it is better to avoid self-diagnosis and consult a general practitioner (family doctor) who knows you personally and your medical history. As for new mutations of the virus – it is possible that existing vaccines will eventually lose some or all of their effectiveness, but at the time of this writing, all registered drugs provide effective protection against the virus. Go back to the beginning.
After the vaccine is administered, it is necessary to remain under medical observation for some time – just in case, to rule out the possibility of a dangerous allergic reaction. But even after that, it is better not to drive until the end of the day. Contrary to popular belief, complete abstinence from alcohol for a few weeks after vaccination is not on the list of requirements. Doctors only recommend abstaining from alcohol for a few days immediately after the injection, as alcohol in the bloodstream hinders the formation of immunity to any disease. After that you can return to your normal routine (the main thing is not to abuse it). Other recommendations are virtually the same as those given by doctors after any vaccination. It is better not to wet or rub the injection site for one or two days, and for several days it is necessary to reduce physical (and, if possible, emotional) stress. In general, do not forget that your body may be temporarily weakened, so avoid hypothermia or overheating (e.g. in a bath or sauna), as well as foods that may cause an allergic reaction. Return to the beginning.
Most people tolerate the vaccine without significant symptoms: mild weakness, pain, redness or swelling at the injection site, mild muscle discomfort, sometimes a slight increase in temperature, much less common – mild chills, nausea, possibly a slight enlargement of the lymph nodes. All of these are completely normal reactions when building immunity. Vaccinated individuals pose no danger to those around them during this time. It is recommended not to lower the temperature below 38 degrees. If it has risen above this, you can take a fever-reducing medicine that you usually use for colds, preferably acetaminophen. In rare cases, the fever may persist for two to three days. Serious side effects are extremely rare. For example, according to recent studies, evidence of thrombosis occurs in 4-5 people per million vaccinated (0.0005%) compared to 39 cases per million unvaccinated patients who received COVID-19. Thus, according to preliminary data, the vaccine reduces the risk of COVID-19-related thrombosis by approximately eight times (remember, the infection will reach everyone). Go back to the beginning.
Almost all coronavirus vaccines available today (except Johnson & Johnson and the “light” version of “Sputnik”) require two doses. This means that some time after the first injection, you will need a second injection to increase the protection. In the clinical trials, the second shot was given several weeks after the first (usually after 21 or 28 days), but it is very possible that you will be offered to postpone the second shot for a few months – or (in the case of “Sputnik”) to skip it altogether. Experts say it is still worthwhile to be vaccinated: the first shot should trigger the body’s immune response and provide at least partial protection. This should be enough to prevent severe progression of the disease. If you caught a cold after the first injection, it is better to postpone the second one a bit (how much – see here). Doctors say that there can be a break of up to two months between the administration of the first and second dose – without any loss of effectiveness of the vaccine. Maximum protection against coronavirus infection is achieved three to four weeks after the second vaccination, when full immunity is established. However, even in this case, a vaccinated person can carry the virus without knowing it. Therefore, even after vaccination, it is necessary to continue wearing a mask and keeping a distance from others for their protection. Return to the beginning.
Vaccination is strongly recommended only for those who have never had COVID-19 (or who have had an asymptomatic infection and are unaware of it).
If you are sure that you have had COVID-19 in the last six months, it is better to wait at least a few months before vaccination. If you suspect that you have had a coronavirus infection, but an official diagnosis of Covid-19 has not been confirmed, it is useful to have an antibody test before vaccination. However, it is important to remember that the presence of antibodies does not guarantee protection. Scientists still do not know what level of antibodies provides reliable immunity and how linear this relationship is. There is a version that the key role in the fight against Covid-19 is not played by antibodies, but by cellular immunity: with the help of memory cells, the body somehow remembers the infection and quickly produces the necessary antibodies when it encounters the virus again. However, the immunity provided by having had the disease is different from the protection provided by a vaccine. Therefore, at some point – when more vulnerable populations are vaccinated – even those who have had the disease are strongly encouraged to be vaccinated. In any case, doctors recommend that those who have already recovered take an IgG antibody test to make sure their levels have dropped sufficiently. Return to the beginning.
Short answer – definitely yes. Mutation – that is, genetic change under the influence of the environment – is an integral and even defining characteristic of every living organism, from single-celled bacteria to us. The virus is not alive, but it “comes to life” by entering a cell where it begins to replicate, producing its own copies. However, not all of them are identical to the original: during the assembly of each new viral particle, there can be a malfunction in the RNA chain, giving rise to a new variant of the virus. Today, the number of viral genome variants in the world is in the thousands, but vaccines developed long before new strains emerged still provide excellent protection against infection. Scientists cannot rule out the possibility that sooner or later the virus will mutate to such an extent that some of the existing vaccines will become less effective. However, a number of studies (most notably on Pfizer’s and Moderna’s RNA vaccines) have shown that even if this were to happen, the composition of the vaccine would probably only need to be slightly modified, similar to the annual changes made to the flu vaccine. In addition, active research is being carried out into the combination of different vaccines: where the first injection is given with one vaccine and the second with another. The theory is that this will make the immune protection of vaccinated individuals even more reliable. Go back to the beginning
Scientists do not yet have an exact answer to these questions because Sars-Cov-2 was discovered only a year and a half ago. However, based on the dynamics of virus mutation and experience in studying related pathogens, it is likely that immunity will not last very long. According to recent data, a person remains immune to re-infection for at least eight to nine months after recovery from the disease, and most likely not less than a year – although this is a highly individual indicator and this period can vary widely from person to person. However, as mentioned above, the immune protection acquired through vaccination is different from natural immunity. According to scientists, the effect of the vaccine can last up to two years (and possibly longer). But we will only know for sure in two years. The most important thing for anyone to know is that the vaccine does not protect against infection, but against serious disease. The chance of dying from the coronavirus or being admitted to intensive care as a result of the vaccine is virtually zero. The possibility of being hospitalized or experiencing a mild form of Covid-19 at home after vaccination remains, but is significantly reduced. Go back to the beginning
Simple answer – there is, but don’t rely on it too much. First, immunity does not develop immediately after vaccination; it takes one and a half to two weeks, depending on the type of vaccine received. During this time, the concentration of antibodies in the body (and therefore the level of immune protection) slowly increases, and all figures below refer to the maximum level. According to preliminary research data, the first dose of the Comirnaty (also known as Pfizer/BioNTech) vaccine reduces the risk of death from Covid-19 to zero – as well as the likelihood that a vaccinated person will require hospitalization in the event of infection. Protection against coronavirus infection with relatively mild symptoms is estimated to be at least 50%. However, some experts believe it is “no less than 80% – and possibly more than 90%”, at least for three to four weeks after the first dose. Moderna’s vaccine also shows very similar results. One dose of the Oxford/AstraZeneca vaccine provides at least 70% protection against Covid-19 (which is severe enough to cause symptoms) for at least three months. The Russian vaccine “Sputnik V” provides approximately the same level of protection, as both vaccines are produced using very similar technology. Preliminary data show that the effectiveness of the “Sputnik Light” vaccination (i.e. the first dose) is close to 80%, although the corresponding clinical trials are still ongoing and will not be completed until February 2022. Return to the beginning.
The first vaccine injection triggers the immune system’s formation mechanism. Specifically, the injection of a foreign protein (or other antigen, depending on the type of vaccine) causes the body to begin producing antibodies capable of neutralizing the “invader”. However, as numerous studies have shown, antibodies alone are not enough to provide reliable protection against the virus. It is necessary for the body to remember the infection, i.e. to store information about it in specialized “memory cells”. The next time they encounter the coronavirus, these cells can re-initiate the antibody production pathway and quickly organize an effective immune response. T-killers also play an important role in the fight against infection, destroying infected cells in the body and preventing the virus from spreading. This requires (to simplify the scientific explanation) a second injection. Some experts compare antibodies to a sword that fights infection, and T cells and memory cells to a shield that protects against it. Return to top
There is some disagreement among experts about the interval between two doses of the vaccine. On the one hand, during clinical trials, volunteers received the second dose of the vaccine 2-3 weeks after the first – and the reported efficacy figures are based precisely on such an interval between injections. On the other hand, it is necessary to remember that clinical trials of all vaccines were conducted under emergency, unprecedented conditions, and developers tried to save time to the maximum. So the same 2-3 weeks break is the minimum possible time between two doses, but in reality it can be longer. In addition, delaying the second dose by a month or more can significantly increase the effectiveness of the vaccine. For example, the second dose of the Oxford vaccine given within six weeks of the first dose provides about 55% overall protection, but if it is delayed for three months, the vaccine’s effectiveness increases to 81%. At the same time, it is not recommended to delay the second injection too long. The WHO recommends that the interval between two doses should not exceed 12 weeks. All of the above can be summarized as follows. If you were asked at the vaccination site to come back in two weeks for the second dose of the vaccine – come back in two weeks. But if for some reason you missed the scheduled time for the second shot, don’t worry – you can get it in two or even three months. Return to the beginning.
The simple answer is yes, but with some caveats. The most important caveat is that each vaccine has its own list of contraindications. So if for some reason you have decided to have another vaccination, with a different vaccine, be sure to check with your doctor first. For the rest, however, studies show that mixing vaccines can be not only safe, but also beneficial. For example, in volunteers who received their first shot of the AstraZeneca vector vaccine and their second (booster) shot of the Pfizer mRNA vaccine, the concentration of specific antibodies in the body increased by an average of 30 to 40 times. Experts say the same should be true for any combination of two other vaccines made with different technologies – and no additional research is needed to prove it. As Professor Daniel Altman, an immunology expert at Imperial College London, assures readers of the journal Nature, such a reinforcing effect “comes absolutely from the basic principles of immunology. Go back to the beginning
The article was written using materials and recommendations from the World Health Organization, the Ministry of Health of Russia, the National Health Service of the United Kingdom, the Centers for Disease Control and Prevention of the United States, vaccine developers, and other sources.
