There are two main reasons why scientists try to come up with a vaccine for an infection: either the infection is very serious or the infection is very common (and sometimes both situations are true). In the case of the rotavirus vaccine, it is because of the latter. Rotavirus infection is rarely life threatening in the United States, even though it is responsible for the deaths of half a million children around the world each year. The majority of deaths occur in developing countries where there is not easy access to a medical facility. In 2007, less than fifty American babies died from rotavirus infection.
The rotavirus vaccine works well to keep children out of the hospital. Even if the vaccine does not completely prevent diarrhea caused by this virus, it prevents hospital admission 96 percent of the time. The vaccine first became widely used in 2006, and the 2007–2008 rotavirus season was drastically different from previous years. Not only did the season arrive later, but the magnitude of the outbreak was significantly reduced.
Your child does not become immune to this virus after a previous infection. However, the infection is usually less severe the second or third time around. Rotavirus does not pose a serious problem to older children and adults because they were probably exposed to this virus before.
The rotavirus vaccine differs from many other vaccines in that it is not injected into the body with a needle. Instead, this vaccine comes in a small single-dose vial and is administered directly into the mouth of your child from the prepackaged vial. The vaccine contains a very small amount of liquid (2 ml, or 2 cc, to be exact), and the direct administration of the vaccine without using a syringe avoids contamination of the vaccine.
A new rotavirus vaccine became available in June 2008. It is called Rotarix, and it is similar to the RotaTeq vaccine. The difference between these two vaccines is that the virus in the Rotarix vaccine is weakened by a different method than the RotaTeq vaccine. Both vaccines have been demonstrated to be safe.
Three doses of the vaccine are routinely recommended — one at the two-month, one at the four-month, and one at the six-month visit. However, all three doses of this vaccine must be given within a small window of time. Unlike many other vaccines, where a catchup dose can be given months or even years after the initial dose, the first dose of the rotavirus vaccine must be given prior to twelve weeks after birth, and the rotavirus vaccine cannot be given after thirty-two weeks of age (around eight months old). If your child missed this vaccine at the two-month well baby visit, she cannot get this vaccine at the four-month visit. The reason for this small window of time is that this vaccine has not been tested in younger infants and older infants. Whether this vaccine is safe for older children (children older than eight months) is unknown.
If your baby spits up some of the rotavirus vaccine right after it was administered, a repeat dose is not recommended. However, your baby can still get the remaining doses in the vaccine series.
Similar to the measles and chickenpox vaccine, the rotavirus vaccine contains live but weakened virus, so it should not be given to babies who have a defective immune system (such as infants with leukemia, lymphoma, or AIDS, or infants undergoing chemotherapy). If your baby had received a blood transfusion in the past six weeks, she should not receive the rotavirus vaccine until later.