One dose of H1N1 vaccine may provide sufficient protection for infants and children

Dec 21, 2009

One dose of vaccine may be effective to protect infants and children and reduce transmission of the H1N1 virus, according to a study in JAMA, published online today because of its public health implications. The study will appear in the January 6 print edition of the journal.

Initial reports of 2009 influenza A(H1N1) infection in many countries have largely involved children, especially those attending school. Reports have also indicated high hospitalization rates of children younger than 5 years of age in the current pandemic, according to background information provided by the authors. "The Advisory Committee on Immunization Practices also currently recommends that infants and children aged 9 years or younger receive two doses of H1N1 at least 21 days apart, based on existing experience with seasonal trivalent influenza vaccines in this age group."

Terry Nolan, M.B.B.S., Ph.D., from the University of Melbourne, Australia and colleagues assessed the effectiveness and safety of two doses of a 2009 influenza A(H1N1) vaccine in 370 healthy infants and children ages six-months to less than 9 years living in Australia. The children were randomized into groups that received a two-injection regimen 21 days apart in doses of either 15-micrograms or 30-micrograms of the vaccine.

"Following the first dose of vaccine, antibody titers of 1:40 or greater were observed in 161 of 174 infants and children in the 15-microgram group (92.5 percent) and in 168 of 172 infants and children in the 30 microgram group (97.7 percent)," the authors report. "All participants demonstrated antibody titers of 1:40 or greater after the second vaccine dose," [which means that every child achieved an antibody level considered high enough to protect against the H1N1 virus]. The researchers note that the majority of adverse reactions to the vaccine were mild to moderate in severity. The immune responses to the vaccine were strong regardless of age, baseline antibody status, or whether the child had received a seasonal vaccination prior to this study.

"Our findings suggest that a single dose 15-microgram dose regimen may be effective and well tolerated in , and may have positive implications for disease protection and reduced transmission of H1N1 in the wider population," the authors conclude.

Explore further: CHOP global health focuses on children with cerebral palsy in southern Africa

More information: JAMA. 2010; 303[1]:[doi:10.1001/JAMA.2009/1911].

Related Stories

Single flu dose or two? Why doctors aren't sure

Sep 02, 2009

(AP) -- Why do scientists warn it may take two doses of vaccine to protect against swine flu when one dose is the norm in a regular flu season? Blame your naive immune system.

Recommended for you

'Ebola will return', veteran scientist warns

7 hours ago

Congolese expert Jean-Jacques Muyembe may be little known to the public, but he has been one of the world's top Ebola investigators since the first epidemic erupted in central Africa in 1976.

Score IDs patients with upper extremity DVT at low risk

23 hours ago

(HealthDay)—For patients with upper-extremity deep vein thrombosis (DVT), six easily available factors can be used to create a score that identifies those at low risk of adverse events during the first ...

Combined drug treatment combats kidney disease

May 29, 2015

A recent discovery by drug researchers whereby coupling specific cell membrane receptors has altered kidney cell function has triggered a re-think of how to treat chronic kidney disease (CKD) more effectively.

Active substance targeting dreaded hospital germs

May 29, 2015

In the German Center for Infection Research (DZIF), scientists have conducted clinical studies on an active substance against the dreaded hospital pathogen Staphylococcus aureus: a highly effective protein from bacteriophages ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.