The vaccines act by stimulating the immune system to produce antibodies, which can fight infections, preventing the individual from getting sick. Some vaccines are safe during pregnancy, others are not.
Immunization through vaccines protects both the mother and the fetus against various diseases. Ideally, all vaccines should be given before pregnancy, but their administration during pregnancy may be indicated in some situations.
Every time we come in contact with a germ, our immune system creates antibodies against them to aid in their combat. In many diseases, the presence of these antibodies is sufficient to prevent the germ from attacking us again in the future. Infections such as chicken pox, rubella, mumps, mononucleosis, toxoplasmosis, etc. only occur once in a lifetime through the production of specific antibodies.
The rationale behind the vaccine is to try to stimulate the body to produce these antibodies without having to be previously ill. The vaccine presents to the immune system a bacterium or virus in such a way that there is stimulus for the production of specific antibodies, but there is no development of the disease.
A vaccine only acts against a single germ. For example, the rubella vaccine only creates antibodies against rubella itself. There are cases, however, where it is possible to mix more than one vaccine into a single injection, such as the MMR vaccine, which is measles, rubella, and mumps vaccine.
The great difficulty in developing a vaccine is to create it so that the bacteria or virus can stimulate the immune system to create antibodies but are not capable of causing disease. Sometimes it is enough to expose the organism to the dead bacterium or virus to produce antibodies and make the patient immune to this germ. However, not all dead viruses or bacteria are able to stimulate the immune system, causing us to find other solutions to immunize the patient.
There are basically 4 types of immunizations:
A. Vaccines with live attenuated germs
B. Vaccines with fragments of germs (dead germs)
C. Toxoids
D. Immunoglobulins
In pregnancy, the last three options are usually safe, while vaccines with live viruses or bacteria are contraindicated.
Vaccines indicated for those who want to get pregnant
Every woman of childbearing age who intends to have children should inquire about the indicated vaccines before a pregnancy. There are potentially very serious diseases during pregnancy that can be prevented with a simple vaccine.
If you intend to become pregnant in the short term it is important to know your immunization status against the following diseases:
Rubella
Lightning
Chicken pox
Measles
Vaccines for these 4 diseases are made with live attenuated virus and are contraindicated during pregnancy. Therefore, if the patient is not immunized against any of the four, vaccination should be done at least 28 days before the start of a pregnancy.
If you have missed your vaccination card and can not remember if you have had these diseases, it is possible to perform blood tests, called serology, to look for the presence of antibodies against these four diseases. Those who have had the disease or been vaccinated against it in childhood usually have antibodies and do not run the risk of contracting them during pregnancy.
It is important that the pregnant woman is immunized against each of the four infections before becoming pregnant, since once pregnant, the patient may be more vaccinated, having to twist to avoid becoming infected during pregnancy.
Women living in areas endemic for yellow fever should also be vaccinated if the last dose has been applied for more than 10 years. The vaccine can not be used in pregnant women, so it is important to be properly immunized when the pregnancy arises.
Ideally, women should be vaccinated against preventable diseases before pregnancy. When it is chosen to vaccinate a pregnant woman, the benefits to the mother and fetus should always be greater than the potential risks. There is no evidence of harm to pregnant women or fetuses from the administration of dead germ vaccines. On the other hand, live germ vaccines can be harmful to the developing fetus.
To avoid complications to the fetus, most vaccines should be given only before or after gestation. However, there are situations where the administration of vaccines may be indicated during pregnancy. In general, the permitted vaccines are those made with dead germs or toxoids (inactivated toxins). Let's talk a little bit about some of the vaccines that can be applied during pregnancy.
a. Influenza
Pregnant women are at particularly high risk of developing influenza complications. Therefore, vaccines against seasonal influenza and influenza A (H1N1) are recommended for all pregnant women during flu season, regardless of their pregnancy trimester.
The Influenza vaccine protects not only the mother, but also the baby during its first 5 months of life. Women can breastfeed after receiving these vaccines.
b. Tetanus, diphtheria and pertussis
The triple tetanus, diphtheria and pertussis vaccine is routinely administered during childhood and a booster vaccine is recommended every 10 years during adult life. Since all three vaccines do not contain live bacteria, they can be safely administered during pregnancy.
Tetanus is a common cause of neonatal death, especially in poorer countries, where obstetric care presents problems. All unvaccinated women, or the last booster dose for more than 10 years, should receive the tetanus vaccine after the 20th week of gestation. If the adult triple vaccine with tetanus, diphtheria and pertussis is available, better still.
c. Hepatitis A
The Hepatitis A is usually transmitted by an infection contaminas water and may cause premature labor and problems for the fetus. The hepatitis A vaccine is also made with killed virus, so it presents low risk in pregnancy. However, there is still little experience of its use in pregnancy, and some side effects may still be unknown. In general, this vaccination is not indicated during pregnancy, but it can be used in special cases, such as in pregnant women living in areas lacking basic sanitation, that is, pregnant women at high risk of contamination.
Women who have had hepatitis A at some point in their lives are immune and do not need to be vaccinated. Serology is used to identify patients previously immunized.
d. Hepatitis B
The hepatitis B is a sexually transmitted infection by or blood. The hepatitis B vaccine is made with killed virus and is safe during pregnancy. Its administration is done with 3 doses in an interval of 6 months. The vaccine is indicated for all pregnant women who are at high risk of contamination, such as health professionals dealing with blood or needles, women whose partner is the carrier of the virus, sex workers, users of intravenous drugs, etc. If necessary, hepatitis B immunoglobulin may also be administered during pregnancy.
Pregnant women who have had hepatitis B at some point in their lives are immune and do not need to be vaccinated. Serology is used to identify patients previously immunized.
e. Pneumococcus
Pneumococcus is a bacterium that usually causes infections such as pneumonia, meningitis, sinusitis, otitis ... Its vaccination is indicated in people over 19 years old who present a high risk of infection by this bacterium, such as diabetics, immunosuppressed, smokers, alcoholics, patients patients with asthma or chronic bronchitis, people working in nursing homes, etc. The fact that the woman becomes pregnant does not prevent her from taking the vaccine if she shows any of the above. Obviously, the ideal is always to take it before pregnancy, but often this does not happen. In pregnant women, the pneumococcal vaccine is usually administered from the second trimester of pregnancy.
f. Meningitis
The vaccine against meningitis is made with dead bacteria and can be administered during pregnancy if indicated. However, like almost all other vaccines, it is best to administer it before or after pregnancy.
g. Rage
The human rabies vaccine is made with killed virus and can be applied during pregnancy if the pregnant woman has any risk factors such as being bitten by a dog or a bat. The pregnant woman can take both the vaccine and the immunoglobulin against rabies if the doctor feels it is necessary. Treatment in pregnant women is equal to that of non-pregnant women.
Vaccines made with live germs should not be applied during pregnancy. When necessary, it is best to take a gap of at least one month between vaccination and early pregnancy so that there is no risk to the fetus. If the patient is of childbearing potential and is likely to be pregnant, and this includes having had intercourse without contraceptive methods in the last 2 to 3 months, live germ vaccines should be avoided until evidence is provided that the patient is not pregnant . A simple pharmacy pregnancy test helps to identify pregnancies not yet known.
Yellow fever
The Yellow Fever is a viral disease transmitted by mosquitoes. The disease is endemic in some areas of Africa and South America, including the North and Midwest of Brazil.
Pregnant women should avoid trips to regions where there are cases of yellow fever. The vaccine against this disease is made with live virus and can not be given to pregnant women.
If the patient is pregnant where there is a yellow fever epidemic, vaccination may be indicated if an infectologist finds that the risk of infection is greater than the risk of side effects during pregnancy. It is a special case that should be evaluated individually by a specialist. In 99% of cases, the yellow fever vaccine is contraindicated in pregnancy.
