Inactivated poliovirus vaccine in Chilean infants
Professor Miguel O'Ryan, WAidid board member, suggest this week the article, funded by Bill & Melinda Gates Foundation, "Inactivated poliovirus vaccine given alone or in a sequential schedule with bivalent oral poliovirus vaccine in Chilean infants: a randomised, controlled, open-label, phase 4, non-inferiority study", recently published on The Lancet - Infectious Diseases.
SUMMARY:Successful immunisation programmes with trivalent oral poliovirus vaccines (tOPV) or inactivated poliovirus vaccines (IPV), containing poliovirus types 1, 2, and 3 have eliminated wild-type poliomyelitis in many regions, including the Americas. However, live-attenuated Sabin viruses from OPV could revert to virulence, causing vaccine-associated paralytic poliomyelitis (VAPP), or acquire neurovirulence and transmissibility as circulating vaccine-derived polioviruses (cVDPV). Although no cases of poliomyelitis caused by naturally circulating wild-type poliovirus type 2 have been reported for more than 15 years, type 2 vaccine-related viruses continue to induce paralysis. Thus, the World Health Organization (WHO) recommends eliminating type 2 vaccine virus by replacing tOPV with bivalent OPV (bOPV) vaccine containing only types 1 and 3 by April 2016. Many countries in South and Central America are considering a switch to sequential IPV–bOPV schedules from their three-dose tOPV primary series for protection against polio.The article shows the results of a multicentre, randomised, controlled, three-arm, open-label, non-inferiority study performed at six well-child clinics in community health-care centres in Santiago, Chile. This was the first study to compare the immunogenicity of an all-IPV schedule with sequential IPV and bOPV schedules in a phase 4 study, focusing on humoral responses and intestinal immunity.The authors randomly allocated eligible infants (1:1:1) to one of three polio vaccination schedules: IPV at age 8 weeks and bOPV at age 16 and 24 weeks (IPV–bOPV–bOPV); IPV at age 8 and 16 weeks and bOPV at age 24 weeks (IPV–IPV–bOPV); or IPV at age 8, 16, and 24 weeks (IPV–IPV–IPV). 537 patients were vaccinated.The authors showed that seroconversion rates against polioviruses types 1 and 3 were non-inferior in sequential schedules containing IPV and bOPV, compared with an all-IPV schedule, and proportions of protective antibodies were high with all three. For poliovirus type 2, the IPV–bOPV–bOPV schedule with one type 2 immunisation achieved seroconversion in 77.4% of infants at 28 weeks.The authors concluded that sequential schedules of IPV followed by bOPV were non-inferior to an all-IPV schedule in eliciting systemic immune responses to polio serotypes 1 and 3, giving policy makers flexibility in choosing different schedules to enable and sustain polio eradication.
AUTHORS: Miguel O'Ryan, Ananda S Bandyopadhyay, Rodolfo Villena, Mónica Espinoza, José Novoa, William C Weldon, M Steven Oberste, Prof Steve Self, Bhavesh R Borate, Edwin J Asturias, Ralf Clemens, Prof Walter Orenstein, José Jimeno, Ricardo Rüttimann, Prof Sue Ann Costa Clemens, the Chilean IPV/bOPV study group
To read the article, please click here!
End TB Strategy
WAidid suggests this week the article "World Health Organization. Ethics guidance for the implementation of the End TB Strategy", published in March 2017.
SUMMARY:New tuberculosis (TB) ethics guidance, launched recently by the World Health Organization (WHO), aims to help ensure that countries implementing the End TB Strategy adhere to sound ethical standards to protect the rights of all those affected. Poverty, malnutrition, poor housing and sanitation, compounded by other risk factors such as HIV, tobacco, alcohol use and diabetes, can put people at heightened risk of TB and make it harder for them to access care. More than a third (4.3 million) of people with TB go undiagnosed or unreported, some receive no care at all and others access care of questionable quality. The new WHO ethics guidance addresses contentious issues such as, the isolation of contagious patients, the rights of TB patients in prison, discriminatory policies against migrants affected by TB, among others. It emphasizes five key ethical obligations for governments, health workers, care providers, nongovernmental organizations, researchers and other stakeholders to: provide patients with the social support they need to fulfil their responsibilities; refrain from isolating TB patients before exhausting all options to enable treatment adherence and only under very specific conditions; enable “key populations” to access same standard of care offered to other citizens; ensure all health workers operate in a safe environment; rapidly share evidence from research to inform national and global TB policy updates.
AUTHOR: World Health Organization (WHO)