Concurrent outbreaks of circulating vaccine-derived poliovirus types 1 and 2 affecting the Republic of the Philippines and Malaysia, 2019-2021.

Concurrent outbreaks of circulating vaccine-derived poliovirus serotypes 1 and 2 (cVDPV1, cVDPV2) were confirmed in the Republic of the Philippines in September 2019 and were subsequently confirmed in Malaysia by early 2020. There is continuous population subgroup movement in specific geographies between the two countries. Outbreak response efforts focused on sequential supplemental immunization activities with monovalent Sabin strain oral poliovirus vaccine type 2 (mOPV2) and bivalent oral poliovirus vaccines (bOPV, containing Sabin strain types 1 and 3) as well as activities to enhance poliovirus surveillance sensitivity to detect virus circulation. A total of six cVDPV1 cases, 13 cVDPV2 cases, and one immunodeficiency-associated vaccine-derived poliovirus type 2 case were detected, and there were 35 cVDPV1 and 31 cVDPV2 isolates from environmental surveillance sewage collection sites. No further cVDPV1 or cVDPV2 have been detected in either country since March 2020. Response efforts in both countries encountered challenges, particularly those caused by the global COVID-19 pandemic. Important lessons were identified and could be useful for other countries that experience outbreaks of concurrent cVDPV serotypes.

Australian National Enterovirus Reference Laboratory annual report, 2021.

Australia monitors its polio-free status by conducting surveillance for cases of acute flaccid paralysis (AFP) in children less than 15 years of age, as recommended by the World Health Organization (WHO). Cases of AFP in children are notified to the Australian Paediatric Surveillance Unit or the Paediatric Active Enhanced Disease Surveillance System, and faecal specimens are referred for virological investigation to the National Enterovirus Reference Laboratory. In 2021, no cases of poliomyelitis were reported from clinical surveillance and Australia reported 1.31 non-polio AFP cases per 100,000 children, thereby meeting the WHO's performance criterion for a sensitive surveillance system. The non-polio enteroviruses coxsackievirus A4, coxsackievirus A10, coxsackievirus A13 and enterovirus A71 were identified from clinical specimens collected from AFP cases. Australia also performs enterovirus and environmental surveillance to complement the clinical system focussed on children. In 2021, there were five cases of wild poliovirus reported from the two remaining endemic countries: Afghanistan and Pakistan. Including Afghanistan and Pakistan, 22 countries also reported cases of AFP due to circulating vaccine-derived poliovirus.

Prevalence of transmitted HIV drug resistance since the availability of highly active antiretroviral therapy.

We investigated the prevalence of HIV-1-associated transmitted drug resistance (TDR) in Victoria from the time of first availability of highly active antiretroviral therapy. Drug resistance genotyping was performed on virus present in blood samples collected from individuals with serologically confirmed primary infection, between 1996 and 2007. The significance of any mutations detected was interpreted according to a standardised list of drug resistance mutations. The main outcomes measured were the prevalence by year of TDR to any antiretroviral drug class, the numbers of infected individuals with TDR involving multiple drug classes, and the resistance mutations implicated in all cases. There was an average annual prevalence of TDR of 16%, predominantly associated with nucleoside and non-nucleoside reverse transcriptase (RT) inhibitors and most commonly occurring at codons 41, 103 and 215 in the RT. The prevalence of thymidine-associated mutations remained high throughout the period of study. While mutations known to cause resistance to protease inhibitors were uncommon, they were present in several individuals infected with virus resistant to multiple drug classes. The prevalence of TDR in Victoria is similar to geographical locations outside Australia where HIV-specific drug treatment is widely available. Primary infection with drug resistant HIV is a future treatment issue for the individual patient and for the wider population at risk of infection. At this time TDR shows no sign of waning and our data support recent treatment guidelines recommending baseline testing for TDR before therapy is initiated.