Canadian study finds pertussis vaccine protection drops after 3 years

Pertussis immunization with the acellular vaccine offers high protection during the first 3 years, but immunity tapers off significantly over the next 4 years, Canadian researchers reported today in the Canadian Medical Association Journal (CMAJ).

The study is consistent with what US researchers have found and raise questions about how to make the most of protection. The acellular vaccine was developed to sidestep a relatively high level of minor side effects from the whole-cell vaccine, which is still used elsewhere in the world. Canada has been using the acellular vaccine since 1997, and the United States made the switch in the late 1990s.

Researchers based their findings on public health lab and vaccination data for 5,867 people born in Ontario between 1992 and 2013. Over that time period, 486 people tested positive for pertussis. Immunity was high during the first 3 years after vaccination, but the team found little protection after 7 years. Though the overall risk was small, the odds of contracting pertussis increased by 27% each year. Also, those who got the acellular vaccine for their first three infant doses of the vaccine were twice as likely to get sick compared to those who received the older vaccine when they were infants.

Canada's whole-cell vaccine had lower effectiveness than other brands, but the researchers said their findings suggest it is still better for priming than the acellular vaccine. They said Ontario's pertussis immunization strategy should change to improve pertussis protection, with options including vaccinating pregnant women, reintroducing the whole-cell vaccine for babies, or recommending more boosters for children and adults.

In a related commentary in the same CMAJ issue, Nicole Le Saux, MD, with Children's Hospital of Eastern Ontario, wrote that until newer vaccines are available that offer longer duration of protection, health officials should reassess the best strategy. "Perhaps a booster at 10 years of age should be recommended to reduce the incidence among preadolescents, or perhaps regular boosting throughout life is needed. We don't yet have a clear answer."
Sep 26 CMAJ abstract
Sep 26 CMAJ commentary


'Handshake' antibiotic stewardship proves effective in hospital study

A new study indicates that a less formal approach to antibiotic stewardship known as "handshake" stewardship can be an effective strategy for reducing antibiotic use in hospitals.

In the study, which was published today in the Pediatric Infectious Disease Journal, researchers at Children's Hospital Colorado retrospectively measured antimicrobial use at the hospital from October 2010 to September 2014. During this period, the hospital initiated an antibiotic stewardship program (ASP) that incorporated three main features: No restriction or preauthorization of antimicrobials, a review of all antimicrobials administered to patients by a stewardship team (an ASP doctor and a pharmacist), and in-person communication between the stewardship team and providers on the units during clinical rounds.

This strategy, coined handshake stewardship because a handshake provides personal contact and signifies "conveyance of trust," differs from most stewardship programs, which rely on preauthorization and restriction of certain antibiotics. The idea is to capitalize on direct communication between stewardship teams and doctors.

The study evaluated the program over three phases: Pre-implementation, planning, and post-implementation.

Following implementation, overall hospital-wide antimicrobial use decreased 10.9%, with antibacterial use decreasing 10.3%. Significant reductions in the use of vancomycin (25.7%) and meropenem (22.2%) were observed. Antifungal use decreased by 12.1%, and antiviral use dropped by 16.4%. Since most of the decreases occurred during the post-implementation phase, the authors concluded they were largely attributable to the handshake stewardship approach, rather than unrelated temporal trends or other stewardship activities.
October 2016 Pediatr Infect Dis J study


Brazil reports 46,000 new chikungunya cases

Brazil reported 46,446 cases in the 5 weeks since it previously reported cases, the Pan American Health Organization (PAHO) said in its most recent update, published late last week. Brazil now has 216,102 cases.

All told, countries in the Americas had 47,931 new confirmed, suspected, and imported cases, bringing the 2016 total to 302,940, according to PAHO's Sep 23 report. The previous weekly PAHO updates included 510 and 1,788 new cases, respectively. PAHO also reported 55 new deaths—52 in Brazil and 3 in Colombia—bringing the total this year to 108.

Guatemala accounted for the lion's share of the rest of the new cases. The Central American country added 1,214 cases, for a 2016 total of 4,060. Many countries, though, have not reported on the disease for weeks.

The outbreak began in December 2013 on St. Martin in the Caribbean, with the first-ever cases in the Americas. Since then the region has logged 2,181,422 cases.
Sep 23 PAHO update


CDC announces E coli outbreak in 4 states tied to beef

The Centers for Disease Control and Prevention (CDC) and the US Department of Agriculture's Food Safety and Inspection Service (FSIS) are investigating a multistate outbreak of Shiga toxin–producing Escherichia coli in beef products made by Adams Farm Slaughterhouse in Athol, Mass.

On Sep 24, Adams Farm recalled beef, veal, and bison products processed on various dates in July and August that may be linked to the outbreak. So far, seven people in Connecticut, Massachusetts, Pennsylvania, and West Virginia have gotten sick after eating meat produced at Adams Farm. The patients got sick from Jun 27 to Sep 4, and five have been hospitalized, but no have been reported.

Adams Farm said its meat is shipped to farmers' markets, retail locations, and restaurants in the Northeastern part of the United States. The CDC warns, "Illnesses that occurred after Sep 8, 2016, might not yet be reported due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of 2 to 3 weeks."
Sep 24 CDC statement
Sep 24 FSIS recall notice


Preemptive yellow fever campaign will start in Congo

In its weekly yellow fever situation report, the World Health Organization (WHO) said on Sep 23 that the Republic of the Congo (Congo) is set to begin a preemptive vaccine campaign as news broke of new possible cases of yellow fever in neighboring Kinshasa, in the Democratic Republic of the Congo (DRC).

The current yellow fever outbreak began in January of 2016, in Luanda, Angola. Angola, though, has had no new confirmed cases since Jun 23. The DRC had no new confirmed cases as of Jul 12, but there are new reports of 12 suspected cases in that country, 8 in Kinshasa province.

Last month the WHO and Gavi, the Vaccine Alliance, undertook a massive vaccination campaign across both Angola and the DRC. According to the WHO, as of Sep 20, 20 million vaccine doses have been approved for Angola and 9.4 million doses for DRC. Congo announced it will begin a vaccine campaign shortly, but officials released no further details.

As of Sep 15, Angola has had 4,120 suspected cases and 337 deaths, while the DRC reports 2,770 suspected cases and 16 deaths.
Sep 23 WHO yellow fever situation report


Little improvement for 2-dose flu vaccination for young kids

Two-dose flu vaccination compliance has increased slightly in the youngest children, but haven't changed much for older age groups, according to a new study that looked immunization rates at six sentinel sites from the 2010-2011 season, according to a new report. A team from the Centers for Disease Control and Prevention (CDC) and six states published their findings in the Sep 23 edition of Vaccine.

Health officials recommend that children ages 6 months to 8 years receive two doses of vaccine the first year of immunization to ensure an adequate immune response to the vaccine. The new study is a follow-up to one in 2013 that looked at trends from 8 sentinel sites over the 2007-2008 to 2011-2012 flu seasons that that found poor compliance with the two-dose regimen.

In the new study, two-dose compliance in children ages 6 to 23 months was above 60% for all of the flu seasons, higher than for the 20% or lower compliance the team saw for children ages 2 to 4 years old and those ages 5 to 8 years old. In the older two age groups, compliance was lower in 2014-2015 than it was during the 2010-2011 season.

Researchers said there are several possible reasons for the low two-dose compliance, including confusion among health providers about the complexity and evolving recommendations from the CDC's vaccine advisory group, the Advisory Committee on Immunization Practices (ACIP). They also said parents might not be aware of the importance of the two-dose vaccine recommendation for younger children.

To help boost two-dose compliance, they recommend steps such as improved messaging, more convenient access to the vaccine, greater clinician use of vaccination data systems, and patient reminders for in-office vaccination.
Sep 23 Vaccine abstract

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