A vaccine is a way to show the immune system a threat signature to which, over several training cycles, an immune response will be developed.
Any struggle of the body with an infectious disease is an attempt to recognize the threat signature and develop countermeasures. In the general case, this process is carried out until the full result, that is, until recovery. However, there may be infections that:
- The carrier is killed faster than the immune response is generated.
- Change faster than the immune system can "recognize" pathogens.
- They camouflage and hide in places where it is very difficult to gain access to the pathogen.
Therefore, in some cases it is better to arrange exercises in advance. This is what vaccines are. An adult resident of the city is vaccinated against the most dangerous infections in childhood. During outbreaks of infections or when a person is placed in a dangerous environment, it makes sense to do preventive vaccinations. Travel is one of those situations.
Let's deal with the educational program first, then move on to travel and the list of actions.
Why is travel dangerous?
Suppose you are flying to Africa. There is an increased risk of yellow fever. A simple vaccine will cost you about 1 rubles, along with an appointment with a therapist and treatment room services, a higher-level vaccine - 500 rubles. It is impossible to cure yellow fever with specialized medicines (that is, you can only maintain the resources of the body until it can cope on its own), it is easy to get sick, the mortality rate is about 3%, the main vector is mosquitoes. The vaccine has almost no side effects. Is the vaccination worth it? Maybe yes. But it's up to you.
So, travel is when you are not in the familiar environment that your immune system is used to. After the flight, and as a result of reacting to thousands of new external factors, a slight chaos begins to reign in the body's defenses, and you become less colonially resistant to pathogens. Plus, the new environment may contain pathogens that simply don't exist where you normally live.
The reverse is also true: you can be a carrier of pathogens that are not present in your current environment. And then the locals will not be lucky.
How do vaccinations work?
There are 4 main types:
- You can pick up a weakened version of the pathogen strain, which is similar to a real combat one, but does not pose a threat to a healthy organism. These are vaccinations against chickenpox, influenza, yellow fever and so on. This is the easiest way to learn: “training enemies” act against the immune system.
- It is possible to inactivate viruses and bacteria (for example, by placing them in a formaldehyde medium) and show the body already their corpses. Examples are hepatitis A, tick-borne encephalitis. The immune system finds the corpses of enemies somewhere in the body and begins to train to kill them again and again, because this is “buzz” for a reason. When a familiar strain enters the body, it will be clear what to do with it in general terms, and then the immune response will very quickly be selected based on previously obtained data.
- You can introduce toxoids (weakened or modified versions of microbial toxins) - then the body's defenses will learn to deal with the consequences of the action of bacteria, which will give much more time to form countermeasures in case of infection. It turns out that the symptoms of the disease do not affect you, and the body there calmly and quietly deals with pathogens, and you do not even know that they were. This is, for example, tetanus.
- Everything new that belongs to the “hi-tech” category is modifiers of gene complexes (so that some protein, in addition to the main function, cuts the pathogen’s DNA at the same time, for example), molecular vaccines (when the body is, in fact, provided with a DNA / RNA signature in its pure form) and etc. Examples of molecular vaccines are hepatitis B (enveloped viruses without a core), human papillomavirus and meningococcus.
Note that there is no direct relationship between the type of vaccine and its side effects. You might think that a real live pathogen would be more dangerous than a molecular vaccine, but this is not so. The same yellow fever vaccine is considered one of the safest: the chances of side effects are very difficult to distinguish from the statistical error of measurement methods.
What are the side effects?
The most common case is an allergic reaction. For example, the hepatitis B vaccine can exacerbate an allergy to yeast dough. There are also more complex reactions, but in the general case they are all reversible. For irreversible (severe) consequences, careful statistics are compiled, and the vaccine is not allowed to be used if the specific risk for an individual from a disease with all likelihood of becoming infected, transferred, cured, and so on is lower than the risk of complications. Simply put, it is always rational to use the vaccine when it is recommended in the region.
Most of the side effects are due to the fact that you are releasing a weakened virus, toxin, molecular debris and other exogenous things into the body. To teach the immune system to fight, you first need to hit it a little. She will give an answer, and the furniture may also suffer. But it's a necessary part of defense training.
Does the vaccine only work on one strain?
Not really. Here the comparison with signature analysis is somewhat incorrect. The immune system builds something like a perceptual hash. This means that if you are vaccinated against one of the flu strains, then if you are infected with another, the immune response will be formed faster. That is, the risk of complications is less, the severity of symptoms is weaker.
The influenza virus is like a ball from which surface glycoproteins and proteins stick out. The most important (hemagglutinin and neuraminidase) are mentioned in the name of the strain like H1N1. The flu can mutate one of the proteins and turn into H2N1. Then the coincidence will be partial and the body will simply react less actively. Or a “shift” can occur when both proteins change, for example, in H2N3. Then you have to recognize the threat almost from the very beginning.
Note that this applies to similar stamps of the same disease. In the case of meningitis, for example, we are talking about completely different pathogens, and different vaccines protect you from different sets of meningococci. And meningitis itself can be caused by hundreds of other causes.
That is, in the general case, the vaccine contains one or more strains of the most common type of pathogen. It helps to develop resistance to them and their close versions, to speed up the response time to their slightly more distant versions.
What to do before the trip?
The first step is to look at recommendations for the country from the tour operator or somewhere else before buying a ticket. The best fit is not the memo that you will be given in the travel agency, but the current recommendations of the World Health Organization. It also makes sense to look at the country summary from the same WHO: there are recent outbreaks of infections and their consequences. Check the target country's biosecurity barrier requirements. For example, if you have a flight with a stopover in Africa, you may be required to be vaccinated against a pathogen specific to the transfer airport.
In some cases, without a vaccination document, you may not be allowed into certain countries - this must be checked in advance. Usually this is either a visa requirement or the current epidemiological situation.
An alternative option is to go to the doctor and consult with him. Better not to the local therapist, but to the infectious disease specialist of the hospital, where patients are brought from airplanes. His recommendations will be based on approximately the same sources, but at the same time, he will interpret them more correctly and apply them to your condition, taking into account the collected anamnesis. There are specialists in vaccinations before traveling in Moscow, for example, at the Marcinovsky Institute.
So, you have received a list of mandatory and desirable vaccinations. It is up to you to decide whether to follow the recommendations or not. For example, you may decide that if you don't encounter any animals along the way, then you can skip the rabies shot. Your right. But I remind you: WHO makes recommendations for travelers based on statistics. And if it says what is better to do, then it is better to do it.
I will come a couple of days before the trip, “buff”, and everything will be fine?
No.
Firstly, the time for the deployment of antibodies ranges from a couple of days to 3-4 weeks (this is the initial set, maybe more).
Secondly, some vaccines are given in courses of 2-3 times.
Thirdly, not all vaccines are compatible with each other, that is, it will not work out for everyone and immediately.
This means getting vaccinated three weeks before traveling if you need a couple of new properties in your body, and six months in advance if this is your first visit to a tropical country.
Here is the WHO recommendations page for (without dangerous foci along the way):
It is very good to look at vaccinations at the consular department of the Ministry of Foreign Affairs. Full list Here. There you can see other features of the country.
For example, here for need a cholera vaccine.
Here is another one
And what, you need to defend yourself from all this in Russia?
Yes. Pay attention to notes and vectors. If you do not have a vaccination against Japanese encephalitis in Moscow, then it's okay. The most accessible natural foci are in Vladivostok, and even then not every year. But if you are going to Vladivostok, then you should think about it. In practice, information on the Russian Federation on the WHO website is not very accurate, because data is usually provided for a country that has one or two biomes. We have a very healthy homeland, so the set for Baikal will be different from the set for Krasnodar or Arkhangelsk.
What exactly to do to survive in Russia depends on the type of tourism. If you are going to live in the center of Moscow, then it is enough to get vaccinated against the flu and “refresh” childhood vaccinations in time. If you are going to the taiga or going kayaking, then you definitely need a vaccination against tick-borne encephalitis. If you are going to spend a lot of time with animals or go to caves - from rabies (bats carry it). Well, if you are going to the south or to a village without sewerage, then from hepatitis A. Well, about hepatitis B, it will come in handy in case of assistance in a rural outpatient clinic, a cut in a nail salon, dentistry along the way, or a sudden blood transfusion. Fell, stumbled, woke up - hepatitis B.
Do vaccines last forever?
No. Some allow you to develop lifelong immunity, some act for a long time (for example, diphtheria - 10 years), some very short-term (Japanese encephalitis - for 1 year). Then the effectiveness of antibodies and their production slowly fall.
This means that it's a good idea to start by updating what you missed to update, then add the basic "long-term" stuff, and then get used to it before dangerous trips.
So what to do?
Start right here and now by updating your anti-virus databases. Specifically check your entire set of childhood vaccinations. Get to the doctor and ask him to tell you what vaccinations you need.
Usually you need to update tetanus (this is a set of three pathogens in one vaccine) - this is once every 10 years. Most likely, something else from your childhood vaccinations has also already ended.
By the way, checking the effect of the vaccine is simple: in most cases, you can donate specific antibodies and see if the protection is still working. Only a doctor should prescribe an analysis, because there are “current” versions of antibodies, and there are “long-term” ones. You are interested in the latter.
Then add strategically important vaccines. Usually these are hepatitis A and B, human papillomavirus.
If you often travel to certain regions (or will definitely be there in the coming years) - look at long-term vaccinations like yellow fever, typhoid fever.
And only then act before traveling according to the recommendations of WHO, the Ministry of Foreign Affairs or a doctor.
What is highly recommended for an adult from the set?
- Whooping cough, diphtheria and tetanus - renew every 10 years for an adult. Useful in Russia and everywhere on the planet.
- Hepatitis A - lifelong immunity after a course.
- Hepatitis B - lifelong after the course (but you need to check the titers after 10 years).
- Measles, rubella, mumps - renew every 10 years for an adult.
- Chicken pox is a lifelong immunity after a course or a childhood illness.
- Poliomyelitis - lifelong immunity after the course.
- Meningococcal disease is lifelong if vaccinated at age 5 or older.
- Human papillomavirus - once every 15 years (some retain lifelong immunity, update after checking the titer).
- Tick-borne encephalitis - every 3 years if you like to sit by the fire in Russia.
Is it possible to do everything at once?
No. In one cycle, you can get 1-3 vaccines, then you have to wait a month in the general case before the next.
Some vaccines work, some don't. Live vaccines are usually not given on the same day. Genetically modified vaccines can be done en masse, but no more than three vaccines a day, so as not to increase the load on the body.
BCG, yellow fever vaccines and rabies vaccine (against rabies) - these are usually not given together with other vaccinations and among themselves.
Some vaccines should not be given during pregnancy. This applies to live measles, rubella, mumps and varicella vaccines containing live attenuated viruses.
Most childhood and adult vaccines differ only in dosage. That is, if you are injected with two children's instead of an adult, in most cases this is normal. Counts as one.
Vaccines should not be abused either. Follow only rational recommendations, do not prick everything in a row. The ability of the immune system is not infinite, too much training may not be the best idea either. If in doubt, consult your doctor.
Are there diseases that can be protected from without a vaccine?
Yes. There is no vaccination against malaria, so there are two options - either drink prophylaxis, or be treated when you are already sick. Well, either douse yourself with mosquito repellent every hour and believe that you are lucky.
Specifically, in the case of malaria, look for specific pathogens in the region of travel: some are treated without problems, some are not. Those that don't: It may turn out to be better to drink prophylaxis and suffer from its side effects (often and not very good). Where there are no such pathogens, it may be better to take a chance and splash with a spray. You decide. When there is no flash, these are just guidelines.
You can take prophylactic pills in order not to get infected with HIV, but we hope you don’t really need such trips.
It is also highly recommended to have a first aid kit with you so that if you catch an intestinal infection or worms, scabies or one of the simplest, you have something to help yourself with. It is better to make it with the same specialist who will prescribe vaccinations for you before the trip. Or with your therapist.
When can and when not to be vaccinated?
There are contraindications. In general, if you caught a cold before traveling, you do not need to go to the doctor for a vaccination in the midst of a cold. But the same temperature of 39 and other signs of the disease do not always prevent getting a vaccine. This is especially true for frequently ill children. Therefore, always consult a doctor and do not hide all your conditions and chronic diagnoses.
You can read examples of contraindications .
There are few practical contraindications for not getting vaccinated. For example, for live vaccines, this is HIV infection and other types of immunodeficiencies.
In the case of chronic diseases, the list of vaccines may be longer than usual due to increased specific risks. Plus, you need to look at the contraindications of specific vaccines. All this will be checked by the therapist at a preventive appointment before vaccination in the hospital.
Can I get vaccinated abroad before another trip?
Yes. Moreover, you can buy a vaccine somewhere in a pharmacy in our country or abroad and bring it to your hospital so that they give you documents about it. This is relevant when the required vaccine is not available in hospitals in your city. It is very important to check the sanitary requirements of the hospital for transporting the vaccine before such an operation.
Vaccines for the diseases I need are different. Which one to choose?
The simplest choice is between cheaper and more expensive. As a rule, in a more expensive one, there is either a different principle of pathogen inactivation, or a larger library of strains, or there is something that otherwise increases its effectiveness and reduces the likelihood of side effects.
When there are several vaccines and they are of different types, it is better to consult a doctor or, in extreme cases, use the “default” option.
I returned, and something is not very good for me ...
It is better to go where they will figure out with a guarantee that this is not a Russian infection, because the local therapist can be stumped for a couple of days, which will dramatically affect the prognosis for the development of the disease. That is, it is best to walk (or take an ambulance) to the infectious diseases hospital. Be sure to tell the doctors where you've been and what you've been up to (e.g. tasting raw meat according to local recipes, petting cute bats, kissing a giraffe). Most likely, you have been poisoned or caught a cold, but they will check you for everything that matches your symptoms - from dengue to malaria. These are several analyses. It will be a little scary to see people suddenly lower their masks on their faces, but not very painful and not very long. Such are the laws in the Russian Federation, and, in general, this is good for your personal survival.
And what will happen to the passengers of the plane in which the patient flew?
If you are still sick, then you first need to establish what. Further actions depend on the infection. If it was malaria, then it is almost impossible to transmit it without the presence of mosquitoes on board (unless you poured blood on each other with the whole board, but then you will first need to consult a psychiatrist). The same goes for dengue, zika, chikungunya and yellow fever. But if it is measles or meningococcal infection, everything is different, and measures can be taken. The doctor will inform the Sanepidemnadzor (Rospotrebnadzor), and then they will inform everyone and take measures to protect against biohazards.
I read everything, understood and I want to take root before the trip in a month. How to do it?
Call your hospital and ask if the vaccine is for the pathogen you are interested in. Eat? Say you want her. You will be booked for an appointment with a therapist, then he will examine you, ask around, if there are no contraindications, he will send you to the treatment room. There you will receive a vaccine (an injection in the shoulder, for example), then they will read you a list of symptoms that you need to monitor for the next day. Then sit for half an hour in front of the therapist's office or treatment room. In half an hour, the doctor will look out, make sure that you have not been covered with anaphylactic shock, and let you go home. If it was an injection, then a couple of days it will not be possible to wet and scratch it.
If your hospital does not have a vaccine, then call the next suitable one. Anyway, most likely, this is a paid service, so it doesn’t really matter where you get it. The only thing, do not forget to take the vaccination papers - it is better to file copies of them with your dossier in the main hospital.
Sometimes documents need to be saved for travel. For example, after vaccination against yellow fever, they will give a special book that you need to carry with you to the same Panama. Otherwise, you will be allowed inside the country for a maximum of 12 hours.
Thanks for the advice to Tropicologist Victoria Valikova, founder of the Health&Help volunteer clinic in и . If you are interested in her clinic - .
And here are other publications of "Tutu.Tours" and "Tutu.Adventures": , .
Source: habr.com