Top Infectious Disease News of the Week—September 15, 2019

#5: Maternal Tdap and Influenza Vaccination Coverage Has Increased, But Gaps Remain

An infection with pertussis or influenza in a newborn can lead to serious and severe illness. However, vaccination against pertussis and the flu is not recommended until the ages of 2 months and 6 months, respectively.

In order to create protection against these diseases among newborns, pregnant women in the United States are advised to receive tetanus, toxoid reduced diphtheria toxoid, and acellular pertussis (Tdap) and influenza vaccines.

In spite of these recommendations, a survey conducted by the US Centers for Disease Control and Prevention in 2017-18 found that only 54.4% and 49.1% of pregnant women self-reported receiving the Tdap and influenza vaccinations, respectively.

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#4: Should Clinicians Use N95 Respirators to Prevent Respiratory Illness?

As respiratory virus season approaches, infection control measures will become increasingly important. Personal protective equipment (PPE) is one of the strongest tools in an infection preventionist’s arsenal against the spread of diseases. Respiratory virus season means that we tend to see an influx of cases of adenovirus, parainfluenza, and influenza, which amplifies the need for PPE.

For health care workers and those involved in the care of patients, the US Centers for Disease Control and Prevention (CDC) recommends use of facemasks while in the room with a patient with suspected or confirmed influenza. This would be considered Droplet precautions (ie using a surgical mask to prevent the spread of microorganisms that are spread by close contact to patients sneezing/coughing). On the other hand, the CDC recommends that in a situation involving avian influenza (H5N1, H7, N9 strains), or a case of pandemic influenza with severe symptoms, health care workers should not use a regular facemask, but rather an N95 mask or higher.

This distinction has, in my experience, often inspired conversation and event debate within the infectious disease and infection control community. For many, the question is simple — should health care workers also be wearing N95 masks when caring for patients with seasonal influenza? Investigators of a new study sought to address this very question and to determine if there was a difference in the prevention of seasonal influenza between those staff wearing N95 masks versus regular facemasks.

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#3: FDA Accepts Biologic License Application for Merck's Ebola Vaccine

The US Food and Drug Administration (FDA) has accepted a Biologic License Application for the investigational Ebola vaccine V920, Merck announced today. The vaccine was also granted priority review for the prevention of Ebola Zaire virus.

The vaccine, which is also referred to as rVSV-ZEBOV-GP, has been deployed for use in the ongoing Ebola outbreak in the Democratic Republic of the Congo. In July 2016, the vaccine was granted a Breakthrough Therapy Designation by the FDA.

According to Merck, the vaccine was initially engineered by scientists from the Public Health Agency of Canada’s National Microbiology Laboratory and then licensed to a subsidiary of NewLink Genetics Corporation. During the western Africa Ebola outbreak in 2014, Merck licensed the vaccine and began working with external collaborators to bolster a clinical development program.

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#2: UV Disinfection Tackles MRSA—What About C Diff?

Health care environments are dirty. There’s no way of avoiding it — hospitals, urgent care facilities, and other medical centers are constantly battling microorganisms. Cleaning and disinfection are critical in these environments to help reduce the risk of transmission. Consider that roughly 1 in 100 people carry methicillin-resistant Staphylococcus aureus (MRSA) while 1 in 3 carry drug-susceptible S aureus in their nose.

Organisms like MRSA, Candida auris, and Clostridioides difficile, are known to cause diseases in these settings and are often culprits in health care-associated infections. Effectively removing these organisms from the environment is critical for infection control efforts. While disinfecting wipes and sprays have been the go-to for decades, ultraviolet-A (UV-A) light exposure has been growing in popularity. While UV-A is a method for disinfecting surfaces and objects, it can’t sterilize products, but it can help reduce bio-burden in patient rooms, waiting areas, operating rooms, and other high-risk areas. Like many new technologies, UV-A disinfection is still finding its way into hospitals as people become more comfortable with its infection control capabilities.

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#1: Antibiotics May Disrupt Gut Microbiome and Inhibit Immune Responses to Flu Shot

As influenza season draws near, public health officials are once again recommending vaccination with the seasonal flu shot for all individuals >6 months.

But now, a new study published in Cell, reports that oral antibiotics, which may alter or kill microorganisms in the gut microbiome, can affect immune responses to the seasonal influenza vaccine. The research was funded by the National Institute of Allergy and Infectious Diseases.

For the investigation, a team of researchers examined 33 adult participants. The first group, comprised of 22 participants was studied during the 2014-15 influenza season and the second group, made up of 11 participants, was studied during the 2015-16 influenza season.

According to the investigators, led by scientists at Stanford University, the participants in the first group had high pre-existing immunity to the virus strains contained in the seasonal flu shot of 2014-15; however, the group of 11 participants had low immunity to the virus strain in the 2015-16 vaccine.

Each of the enrolled participants received a seasonal flu shot. To evaluate the role of antibiotics, half of the participants in each group also received a 5-day oral course of a broad-spectrum antibiotic regimen containing neomycin, vancomycin, and metronidazole prior to vaccination.

The participants were required to submit stool and blood samples at various points up to 1 year after vaccination. The investigators analyzed the samples and tracked each participant’s immune response to the vaccine and observed the diversity and number of organisms present in their gut microbiomes.

Just as the study team hypothesized, most participants who received the 5-day course of broad-spectrum antibiotics had reduced levels of gut bacteria.

According to a press release, the study team observed that among the participants during the 2015-16, who had little prior immunity to the vaccine strains, the course of antibiotics hindered immune responses to 1 of the 3 virus strains in the vaccine, which were an H1N1 A/California-specific virus.

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