[afro-nets] BBC: Diarrhoea vaccine tests 'hopeful'

[Leela McCullough <leela@healthnet.org>]

BBC: Diarrhoea vaccine tests 'hopeful'
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Forwarded from E-Drug

http://news.bbc.co.uk/2/hi/health/4580482.stm

Diarrhoea vaccine tests 'hopeful'

Promising findings from two studies are offering the hope of a
safe and effective vaccine against the most common cause of
childhood diarrhoea.

Rotavirus kills about 500,000 children a year in developing
countries, and accounts for a third of hospital admissions from
diarrhoea worldwide.

The New England Journal of Medicine reports on tests of vaccines
Rotateq and Rotarix involving 130,000 children.

The studies found them to be 98% and 85% effective respectively,
it says.

Rotavirus is endemic and infections occur in almost all children
by the time they are two or three.

The severity of infection ranges from no symptoms, through vom-
iting, fever, abdominal pain and watery diarrhoea to dehydrating
gastroenteritis, which can be fatal.

In the UK, it is estimated that 1 in 38 children will be hospi-
talised for rotavirus gastroenteritis by the age of five, and
that each year 14 children under five will die.

Most infections occur in children under two.

It is so devastating to children in the developing world because
of the lack of prompt access to treatment and hospital care.

The quest for a safe and effective vaccine against the virus was
thought to be over in the late 90s when a previous vaccine was
developed.

But that had to be withdrawn from the market after it was asso-
ciated with an uncommon, but potentially life-threatening condi-
tion called intussusception, where the bowel folds in on itself,
causing an intestinal blockage.

Side effect checks

The first study - involving more than 68,000 infants aged six to
12 weeks - found a vaccine called Rotateq being developed by the
pharmaceutical company Merck could safely prevent 98% of severe
cases of viral diarrhoea and vomiting.

Rotateq targets five major strains of rotavirus, which account
for 90% of rotavirus disease.

The trial involved infants in the US, Belgium, Costa Rica,
Finland, Germany, Guatemala, Italy, Jamaica, Mexico, Sweden and
Taiwan.

Half were given the vaccine and half a dummy version.

All were monitored to ensure there were no side effects, includ-
ing intussusception.

There were no more side effects seen in the vaccine group than
their peers.

The results of a trial of another oral vaccine called Rotarix,
developed by GlaxoSmithKline, showed it was effective against
the most common strain of rotavirus and able to prevent 85% of
severe cases.

Over 63,000 infants were studied in 11 Latin American countries
and Finland for between three months and a year.

Again, no difference was seen in complication rate between chil-
dren given the vaccine and those given a dummy version.

Both studies found vaccination significantly reduced the number
of children who had to be treated in hospital due to rotavirus.

Writing in the NEJM, Dr Roger Glass and Dr Umesh Parashar, of
the US Centers for Disease Control, welcomed both studies as
showing promising results.

"As vaccines become licensed and used in the US and Europe, we
should expect to see a substantial reduction in winter hospi-
talisations, visits to doctors and clinics and parents' workdays
lost to childhood diarrhoea," they said.

But they warned: "Both vaccines will need to demonstrate their
efficacy in the difficult settings of developing countries if we
are to achieve our goal of maximally decreasing global deaths
from diarrhoea."

Dr David Brown, from the Health Protection Agency said: "The re-
sults of these large studies are significant because they demon-
strate that these two vaccines have good efficacy against severe
rotavirus disease and are not associated with intussusception."

  -- Abstract 1 --

Safety and Efficacy of an Attenuated Vaccine against Severe Ro-
tavirus Gastroenteritis
G.M. Ruiz-Palacios and Others
http://content.nejm.org/cgi/content/full/354/1/11?query=TOC

Background
The safety and efficacy of an attenuated G1P[8] human rotavirus
(HRV) vaccine were tested in a randomized, double-blind, phase 3
trial.

Methods
We studied 63,225 healthy infants from 11 Latin American coun-
tries and Finland who received two oral doses of either the HRV
vaccine (31,673 infants) or placebo (31,552 infants) at approxi-
mately two months and four months of age. Severe gastroenteritis
episodes were identified by active surveillance. The severity of
disease was graded with the use of the 20-point Vesikari scale.
Vaccine efficacy was evaluated in a subgroup of 20,169 infants
(10,159 vaccinees and 10,010 placebo recipients).

Results
The efficacy of the vaccine against severe rotavirus gastroen-
teritis and against rotavirus-associated hospitalization was 85
percent (P<0.001 for the comparison with placebo) and reached
100 percent against more severe rotavirus gastroenteritis. Hos-
pitalization for diarrhea of any cause was reduced by 42 percent
(95 percent confidence interval, 29 to 53 percent; P<0.001).
During the 31-day window after each dose, six vaccine recipients
and seven placebo recipients had definite intussusception (dif-
ference in risk, ­0.32 per 10,000 infants; 95 percent confidence
interval, ­2.91 to 2.18; P=0.78).

Conclusions
Two oral doses of the live attenuated G1P[8] HRV vaccine were
highly efficacious in protecting infants against severe rotavi-
rus gastroenteritis, significantly reduced the rate of severe
gastroenteritis from any cause, and were not associated with an
increased risk of intussusception.


  -- Abstract 2 --
Safety and Efficacy of a Pentavalent Human-Bovine (WC3) Reassor-
tant Rotavirus Vaccine
T. Vesikari and Others
http://content.nejm.org/cgi/content/full/354/1/23?query=TOC

Background
Rotavirus is a leading cause of childhood gastroenteritis and
death worldwide.

Methods
We studied healthy infants approximately 6 to 12 weeks old who
were randomly assigned to receive three oral doses of live pen-
tavalent human­bovine (WC3 strain) reassortant rotavirus vaccine
containing human serotypes G1, G2, G3, G4, and P[8] or placebo
at 4-to-10-week intervals in a blinded fashion. Active surveil-
lance was used to identify subjects with serious adverse and
other events.

Results
The 34,035 infants in the vaccine group and 34,003 in the pla-
cebo group were monitored for serious adverse events. Intussus-
ception occurred in 12 vaccine recipients and 15 placebo recipi-
ents within one year after the first dose including six vaccine
recipients and five placebo recipients within 42 days after any
dose (relative risk, 1.6; 95 percent confidence interval, 0.4 to
6.4). The vaccine reduced hospitalizations and emergency depart-
ment visits related to G1­G4 rotavirus gastroenteritis occurring
14 or more days after the third dose by 94.5 percent (95 percent
confidence interval, 91.2 to 96.6 percent). In a nested
substudy, efficacy against any G1­G4 rotavirus gastroenteritis
through the first full rotavirus season after vaccination was
74.0 percent (95 percent confidence interval, 66.8 to 79.9 per-
cent); efficacy against severe gastroenteritis was 98.0 percent
(95 percent confidence interval, 88.3 to 100 percent). The vac-
cine reduced clinic visits for G1­G4 rotavirus gastroenteritis
by 86.0 percent (95 percent confidence interval, 73.9 to 92.5
percent).

Conclusions
This vaccine was efficacious in preventing rotavirus gastroen-
teritis, decreasing severe disease and health care contacts. The
risk of intussusception was similar in vaccine and placebo re-
cipients.

--
Leela McCullough, Ed.D.
Director of Information Services
SATELLIFE
30 California Street, Watertown, MA 02472, USA
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Fax: +1-617-926-1212
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