new YORK (Reuters Health) – in 2010, during an outbreak
cough whooping in California, United States, children
vaccinated between 8 and 12 years were more prone to contracting
the disease than children of other ages, suggesting that
protection decreases with age.
“We are convinced that the length (of the vaccine) is not
“”
which imagined”, said Dr. David Witt, a specialist in
infectious diseases from Kaiser Permanente Medical Center, in
San Rafael, California, and lead author of the study.
The cause of the troubled, cough, or pertussis, is the bacterium
Bordetella pertussis. The infection produces intense cough that lasts
weeks and can lead to pneumonia.
Centers for disease prevention and Control
United States (CDC for its acronym in English) estimated that, each
year, nine of every 100,000 Americans develops the
disease. While the figure is much lower than before of
the appearance of the vaccine, the infection grows from for two
decades.
The DTaP vaccine is applied in five doses at 2, 4, 6 and 18
months of age, and between 4 and 6 years. The CDC recommended
apply a (Tdap) booster dose at age 11 or 12.
In 2010, at Kaiser Permanente San Rafael was recorded
a sudden increase in cases that people tried to finally of a
troubled cough outbreak, the largest in California, more than 50
years.
“We began to analyze the data and we were surprised that the
“
most cases was of children with the full scheme of
vaccination. “That drew our attention,” said Witt.
With his team, the author collected information of each patient
with pertussis confirmed between March and October 2010.
81 Percent of 132 patients under 18 years of age
had the full scheme of troubled cough vaccination and
8 percent had never been vaccinated. 11 Per cent
remaining had received at least one dose.
The rate of cases for every age up to 18 years had a
peak among preteens. 36 Cases were recorded by each
10,000 children with the full scheme of the vaccine among the 2 and
age 7, compared to 245 out of 10,000 children between 8 and 12
years.
“To greater interval since the last dose, increased risk of
“”
get sick”, summarized Witt.
At the age of 13, the number of cases declined, perhaps because
that is the age in which adolescents should receive the dose
booster.
To compare the Group of children infected with more than 2,000
non-infected children registered in the database of the Centre
doctor, the team of Witt found, as he writes in the magazine
Clinical Infectious Diseases, that the vaccine is effective half
often in all boys and 24 percent of the time
between 8 and 12 years old.
“For pertussis, up to 24 percent of protection
“
Help (to mitigate an epidemic), but certainly we would like to
“
than most high”, said.
Dr. Tom Clark, the CDC epidemiologist, indicated that
loss of protection over time explains “the recommendation of
“”
use a booster dose in adolescence”.
For the team, on the other hand, the age of implementation of the
reinforcement would be too late, because it would leave to the
vulnerable preteens to the pertussis bacteria.
But Clark, lower the age of implementation of the Tdap is not
so simple would not solve the problem.
The Dr Joel Ward, of the Research Institute
Biomedical Los Angeles, insisted that parents must
vaccinate their children, even when the protection against cough
troubled diminishes over time.
“The disease was significantly reduced with the vaccine.
“”
The benefit was huge”, said.
Ward, who did not participate in the study, commented that the
immunized children who acquire the infection is not sick
as well as those not vaccinated. In general, the newborn
and young infants are most vulnerable because not yet
were immunized.
Source: Clinical Infectious Diseases, online 15 March of the
2012
