Infectious Disease: Monthly Essentials October 2017

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The 2 essential studies on Infectious Disease this month, selected from 1184 peer-reviewed studies

1. CDC has revised its 2016 US Medical Eligibility Criteria for Contraceptive Use (MEC) recommendations for hormonal contraception among woman at high risk for HIV acquisition. See our essential synopsis of the article from MMWR below.

2. Findings suggest that third trimester timing of maternal tetanus toxoid, reduced diphtheria, and acellular pertussis (Tdap) vaccination is ideal, maximizing transplacental antibody transfer. In infants aged <2 mo, ~78% of pertussis cases and 90.5% of cases severe enough to require hospitalization were prevented. See our essential synopsis of the article from Clin Infect Dis below.

1. CDC updates guidance on hormonal contraception and HIV



Source: MMWR 

Takeaway
  • CDC has revised its 2016 US Medical Eligibility Criteria for Contraceptive Use (MEC) recommendations for hormonal contraception among woman at high risk for HIV acquisition.
Recommendations
  • New recommendations are altered to reflect with WHO updated recommendations (March 2017) that changed MEC category 1 (safe for use without restriction) to MEC category 2.
  • Prevalence of DMPA use in the United States is highest among subgroups that are at increased risk for HIV, unintended pregnancy, and pregnancy-related complications.
  • Implants, progestin-only pills, and combined hormonal contraceptives are MEC category 1 and may be used without restriction among women at high risk for HIV.
  • Although there is evidence for increased risk for HIV acquisition among women using progestin-only injectable contraceptives, data are inconclusive and data quality has significant limitations.
  • DMPA requests should not be denied.
  • Clinicians are advised to counsel at-risk women about a possible increased risk, benefits, alternatives, and HIV prevention, including limiting numbers of sexual partners, consistent condom use, and pre-/postexposure prophylaxis.
Why this matters
  • CDC reports that advantages of progestin-only injectable contraception (including depot medroxyprogesterone acetate [DMPA]) outweigh the theoretical or proven risks in women at high risk for HIV (MEC category 2).

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2. 3rd trimester Tdap vaccine protects infants in first 2 mo of life



Source: Clin Infect Dis

Takeaway
  • Findings suggest that third trimester timing of maternal tetanus toxoid, reduced diphtheria, and acellular pertussis (Tdap) vaccination is ideal, maximizing transplacental antibody transfer.
  • In infants aged <2 mo, ~78% of pertussis cases and 90.5% of cases severe enough to require hospitalization were prevented.
Key results
  • During the third trimester, 7.1% of infants and 16.8% of control infants received the vaccination.
  • VE before pregnancy, during the first/second trimester, during the third trimester, and after pregnancy was 50.8%, 64.3%, 77.7%, and 4.9%, respectively.
  • VE was 78.4% (95% CI, 49.8%-90.7%) when third trimester dosing was restricted to a window of 27-36 wk.
  • VE was 90.5% (95% CI, 65.2%-97.4%) for prevention of pertussis hospitalizations.
Study design
  • This study evaluated maternal Tdap vaccine effectiveness (VE) in the prevention of infant pertussis (infants, n=240; control infants, n=535).
  • Funding: Emerging Infections Program Network.
Why this matters
  • Clinicians should maximize infant pertussis prevention efforts by encouraging maternal Tdap vaccination in pregnant women.
  • Pertussis remains endemic, with US cases steadily increasing since 2012; this is due in part to waning immunity levels.
  • Only 49% of pregnant women delivering babies between fall 2015 and spring 2016 had been vaccinated.

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