Mabalako remains hot spot in ongoing Ebola outbreak in DRC
According to the World Health Organization's (WHO's) online Ebola dashboard, officials in the Democratic Republic of the Congo (DRC) tracked 5 new cases of Ebola today, raising the outbreak total to 3,403, including 2,235 fatalities. The death toll has not changed since last week.
A total of 410 suspected cases are still under investigation.
The DRC's Ebola technical committee (CMRE) said in a report today that three cases recorded yesterday were from Mabalako, which has been the hot spot of virus activity for the last several months. Most recent cases in Mabalako are part of the same Aloya health zone transmission chain.
The CMRE also noted a community attack on outbreak response workers in the Bandibwame health area in Lolwa in Ituri province. Four people were injured. Small pockets of resistance have also been seen in Biakato Mines, Lwemba, Aloya, Bingo, Mangina, and Mabalako.
Study shows middle-age adults at most risk for H3N2 flu
A new study on influenza immunologic imprinting suggests adults who were first exposed to H3N2 influenza A in the late 1960s and early 1970s possess non-neutralizing (ineffective) antibodies against current strains of the virus, making them more susceptible to infection. The study appeared yesterday on medRxiv, a preprint server.
H3N2 first began circulating in humans in 1968, and most people have been exposed to and develop antibodies against the virus by 3 to 4 years of age. But a new clade of the virus—3c2. A H3N2—emerged during the 2014-15 flu season and has since been associated with high rates of severe illness and flu hospitalizations in the United States. The clade has dominated three recent US flu seasons, including the 2017-18 season.
To test how and if age affected immune response to the virus, the researchers collected sera samples from 140 children and 212 adults from hospital systems in Philadelphia during the summer of 2018.
"Sera from children aged 3-10 years old possessed the highest levels of neutralizing antibodies against these viruses (p<0.0007 when compared to all other age groups for both 3c2.A and 3c2.A2 titers), whereas most middle-aged adults did not have detectable neutralizing antibody titers," the authors wrote. "Among adults, neutralizing antibody titers were lowest in individuals ~50 years of age. This is notable since 50 year olds were born in 1967, one year before H3N2 viruses began circulating in humans."
The authors said their findings may help explain why recent flu vaccines have been so ineffective against H3N2, "It may be inherently difficult to design 3c2.A H3N2 vaccine antigens that are able to elicit neutralizing antibodies in humans that were exposed early in childhood with H3N2 viruses in the 1960s and 1970s," the authors concluded.
Jan 13 medRxiv study