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Finally, it bears mentioning that the number of doses can also improve effectiveness for some vaccines. For the flu shot, two doses of the vaccine instead of one can offer a protection boost, but this benefit is limited to only a few specific groups , such as children or organ transplant recipients.
The booster dose does not seem to benefit people over the age of 65 or those with a compromised immune system. By contrast, as we will see below, for vaccines, such as the ones against polio and measles, a higher number of doses is required to achieve peak effectiveness. However, experts recommend IPV in four doses. The CDC recommend that children take one dose of the vaccine at 2 months old, another dose at 4 months old, a third dose at 6—18 months old, and a final fourth dose at 4—6 years old.
Scientists have broken down the side effects that they expect to occur with the BioNTech vaccine — currently the only one with approval for use in the U. Uncommon side effects, which may affect up to 1 in people, include enlarged lymph nodes or feeling unwell. By comparison, the CDC list the following side effects for the flu shot as common:.
Occasionally, they add, the flu shot may cause fainting, like any other injections. The CDC recommend that everyone take the flu vaccine, except for children younger than 6 months of age or those with severe allergies to the flu vaccine or any ingredient in the vaccine. For those that did find such a likelihood, this risk was 1—2 in 1,, people. Rarely, the vaccine may trigger febrile seizures, swelling in the cheeks or neck, or a temporary low platelet count in the blood. Therefore, even if polio vaccination were per cent effective, every person would have to be vaccinated in order to control the disease completely.
The practical problem of immunizing every person in the country is enormous and is further complicated by the need for constantly maintaining a high level of immunization in every individual. The question therefore arises: What is the duration of immunity, assuming that polio vaccination has been effective? In no disease is there permanent immunity after original vaccination. Even where vaccination is highly effective, as in smallpox, it lasts a relatively short time.
Our government requires that those traveling to foreign countries show evidence that they have had successful smallpox vaccination within three years before they can be readmitted to the United States. In polio immunization we must be sure, above all, that we are not postponing the occurrence of the disease from early childhood to later in life when it is more serious.
Paralysis is more severe and death more frequent when the disease strikes in adult life than in childhood. There is no solid evidence at this time concerning the duration of effective polio vaccination because so little time has elapsed since the beginning of the vaccination program. If the polio immunization program continues to be accompanied by a decreasing number of cases, research on the duration of protection from vaccination must be intensified to determine the time when booster doses of vaccine will have to be given.
The evidence that the presently available polio vaccine does not decrease the number of carriers, and the clear-cut vaccine failures, make it apparent that polio will not be eradicated by this means.
Unless the Salk vaccine can be improved, other kinds of vaccine must be developed. At this time, there are two promising lines of investigation. Search must be continued for a virus-killing substance better than formalin to assure a safe vaccine of consistently high potency. Substances such as beta propiolactone have produced in animal experiments effective and safe vaccines with viruses such as that of rabies.
Ultraviolet irradiation, which is being used in combination with formalin by one vaccine manufacturer, deserves further study. The other line of research is the development of live-virus vaccines. This involves converting a virulent live polio virus into a nonvirulent one by successive transfer through laboratory animals.
In the hands of Sabin in Cincinnati and of Koprowski in Pearl River, New York, such avirulent strains when given by mouth have produced immunity in children without causing disease.
But before widespread use of living vaccine can be made, much work remains to be done. We must be sure that these living strains will not revert to their original virulent form. Another theoretical possibility previously successful in another virus disease—yellow fever—is the discovery of a benign strain of living polio virus which may be safely injected and yet produce effective polio immunization. Summarizing the evidence through the autumn of , we can 'draw the following conclusions: The modified polio vaccine manufactured and distributed after November, , has been safe for all practical purposes, but varies from batch to batch in its ability to produce protective substances.
The failure of this vaccine to prevent disease and at times death in certain vaccinated individuals and its apparent inability to reduce the number of carriers clearly indicate that polio will not be "wiped out" by this vaccine. It is impossible to tell how much of the decrease in reported cases of polio in the United States is due to polio vaccination, but it is likely that some of it is due to the vaccine. For purposes of future planning, it would seem reasonable to assume that the polio vaccine has been effective in producing a decrease in the number of cases of polio in the United States in The following points, therefore, are clear: The polio immunization program should be expanded and continued as long as there is a continuing decrease in the number of reported cases of paralytic polio in the United States.
Any upswing in the number of such cases must demand a complete revaluation of the entire program. To maintain a high level of protection in those successfully immunized with the present polio vaccine, it is imperative to determine when booster doses of vaccine will be necessary. Lack of uniform potency of the present vaccine demands its improvement or the development of better "killed" or "living virus" vaccines.
We must maintain an objective attitude in the interpretation of results; we must not relinquish opportunities to improve on present methods and to utilize other means which may prove to be more effective in the conquest of polio.
There is no federal law that requires this. CDC recommends that all children get four doses of inactivated polio vaccine IPV , with one dose at each of the following ages:. All children who have received three doses of IPV before age 4 years should receive a fourth dose at 4 to 6 years of age before or at school entry. For more information, see State Vaccination Requirements. Most health insurance plans cover the cost of vaccines. However, you may want to check with your insurance provider before going to the doctor.
Learn how to pay for vaccines. This program helps families of eligible children who might not otherwise have access to vaccines. You can also contact your state VFC coordinator. Skip directly to site content Skip directly to page options Skip directly to A-Z link. Vaccines and Preventable Diseases. Section Navigation.
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