AT ESPID 2017
MADRID (FRONTLINE MEDICAL NEWS) – Impaired response to measles immunization is common in HIV-infected children, and revaccination – while an important strategy – helps only some of them, Ruth del Valle, MD, said at the annual meeting of the European Society for Paediatric Infectious Diseases.
The key predictor of an impaired response to measles immunization appears to be a CD4/CD8 cell ratio of less than 1.0, added Dr. del Valle of Infant Sofia University Hospital in Madrid.
She presented a multicenter prospective Spanish study of 120 HIV-infected children, with a mean age of 12 years, who received the two doses of MMR which are standard in Spain. Of the participants, 94% were on highly active antiretroviral therapy, and 80% of subjects were HIV virologically suppressed.
Of note, 48% of the children had a CD4/CD8 ratio of less than 1.0 at baseline. This ratio is gaining credence as a predictor of HIV-positive patients’ immunologic response to a variety of vaccines: most recently, in Dr. del Valle’s study, to measles vaccine and, in two earlier studies published in 2016, to yellow fever vaccine ( PLoS Negl Trop Dis. 2016 Dec 12;10[12]:e0005219 ) and hepatitis B vaccine ( Vaccine. 2016 Apr 7;34[16]:1889-95 ).
In Dr. del Valle’s study, only 52% of HIV-positive children developed protective antibody levels following completion of the standard two-dose MMR schedule. In accord with current Paediatric European Network for Treatment of AIDS (PENTA) guidelines, 41 unresponsive patients then received a booster MMR dose ( HIV Med. 2012 Jul;13[6]:333-6 ). Of the 41, 10 (24%) did not respond to the booster dose, either. Thus, the final measles protection rate in this study was only 77%.
These study findings highlight the importance of routinely testing measles vaccine response in HIV-infected children in clinical practice, she noted.
The CD4/CD8 ratio was 1.3 in good responders to measles immunization and 0.9 in nonresponders. In a multivariate analysis, a CD4/CD8 ratio of less than 1.0 conferred a 3.2 times increased risk of impaired response to the measles vaccine.
Dr. del Valle and her coinvestigators in CORISPES (the Spanish Cohort of HIV-infected Children) plan further studies to determine the duration of protection against measles in those patients who responded to the booster dose.
Session cochair Nigel Klein, MD , commented that Dr. del Valle’s study is “one of a number of reports that HIV-infected children, as they get older, are predisposed to getting infections that we should be able to prevent.”
“I think we don’t know best how to manage this population of patients. You can give more vaccinations, but, as Dr. del Valle has shown, not all of them will respond. And I think this study is further evidence that the better we can maintain our children’s immune systems by treating early, the better our chances of getting good responses when we vaccinate,” said Dr. Klein, professor of pediatric infectious diseases and immunology at Great Ormond Street Children’s Hospital and University College London.
Dr. del Valle reported having no relevant financial disclosures.
