Introduction: 2006 Year in Review

December 2006

TOP STORY: Nearly 6,000 confirmed cases of mumps reported in 2006 Future looks bright for next generation of rotavirus vaccines Study review indicates human papillomavirus vaccine safe, well tolerated Children aged 11 to 12 should receive routine MCV4 vaccine again The year 2006: a busy one for varicella Tdap recommendations causing some confusion CA-MRSA in neonates a sign of the times Outbreak of E. coli in spinach led to widespread public health concerns Caution still surrounds fluoroquinolone use in pediatrics Preparing for flu pandemics: A look back can provide clues to the future

Of the hundreds of articles that ran in Infectious Diseases in Children through November, we asked our Editorial Advisory Board to vote on 25 that were deemed to have the most significant impact on clinical practice. They then chose the 10 best. We present summaries of those articles here along with commentary from some of our columnists, where applicable.

Although our selection criteria were not scientific, Chief Medical Editor Philip Brunell, MD, agrees that these 10 articles represent some of the year’s best research in pediatrics and infectious diseases. They signify major changes in the way pediatricians will practice in the years to come.

The most important new vaccine seems to be human papillomavirus, approved for girls as young as 9 years of age and recommended for women up to 26 years of age. The vaccine now licensed contains additional strains, 6 and 11, which are the principal ones causing genital warts. A second vaccine has been submitted for licensure that contains only the two cancer-producing strains. The vaccines have been found to be immunogenic and can decrease the risk of infection and the development of early stages of malignancy.

There are a number of other vaccines approved for adolescents, including rotavirus and combined tetanus-diphtheria-acellular pertussis (Boostrix, GlaxoSmithKline; Adacel, Sanofi Pasteur). In addition, there is a recommendation for a second varicella vaccine, which can now be given in combination with measles-mumps-rubella as MMRV (ProQuad, Merck).

The last two vaccines came in response to public health officials’ concerns about waning immunity. In the case of varicella, the second dose, which may be given as MMRV, was recommended because of the number of partially protected vaccinees following one dose and also because of waning immunity. The second vaccine to arouse concern about waning immunity is MMR, as an outbreak of mumps in people in their 20s, many of whom had received the recommended two doses of MMR, raised concerns. The predominance of cases in these people rather than younger individuals certainly suggests there may be waning immunity.

One example of a disease in which immunity seems to have diminished following vaccination is pertussis. TDaP has replaced dT as the vaccine of choice. These new recommendations have caused some confusion, however, as some officials at the CDC note that TDaP has been given to children inappropriately.

DTaP (diphtheria and tetanus toxoids and acellular pertussis) vaccine is recommended for all infants at 2, 4 and 6 months of age. An additional dose of DTaP vaccine is recommended at 15 to 18 months of age and at 4 to 6 years of age. The TDaP products are recommended for adolescents aged 11 and 12 years.

Also making headlines this year is the newly licensed rotavirus vaccine, with a second on the way. In clinical trials, these vaccines have been shown to reduce the risk of severe diarrhea and are expected to decrease hospitalization for gastroenteritis, a major cause of hospitalization in infants.

Another top story of the year is the appearance of community-acquired methicillin-resistant Staphylococcus aureus in neonates.

The community-associated MRSA problem is becoming more pronounced because of the predominance of the major clone circulating in the community: USA300.

This strain of CA-MRSA is more frequently associated with the Panton-Valentine leukocidin toxin gene, which in some cases can make it more virulent compared with the predominant hospital strains, USA100 and USA200. The PVL gene is a cytotoxin that causes leukocyte destruction and tissue necrosis. The genes that encode for PVL can be transmitted via bacteriophage from one organism to another.

This community-acquired type of methicillin-resistant Staphylococcus aureus makes up a substantial and increasing proportion of Staphylococcus aureus infections in previously healthy neonates. Data from the Morbidity and Mortality Weekly Report and other sources noted CA-MRSA in infants in Chicago, Los Angeles and Texas.

As always, we welcome reader comments about the relevance of these articles on actual clinical practice.

Colleen Zacharyczuk
Managing Editor
czacharyczuk@slackinc.com