Global Trends in Norovirus Genotype Distribution among Children with Acute Gastroenteritis.

Noroviruses are a leading cause of acute gastroenteritis (AGE) among adults and children worldwide. NoroSurv is a global network for norovirus strain surveillance among children <5 years of age with AGE. Participants in 16 countries across 6 continents used standardized protocols for dual typing (genotype and polymerase type) and uploaded 1,325 dual-typed sequences to the NoroSurv web portal during 2016-2020. More than 50% of submitted sequences were GII.4 Sydney[P16] or GII.4 Sydney[P31] strains. Other common strains included GII.2[P16], GII.3[P12], GII.6[P7], and GI.3[P3] viruses. In total, 22 genotypes and 36 dual types, including GII.3 and GII.20 viruses with rarely reported polymerase types, were detected, reflecting high strain diversity. Surveillance data captured in NoroSurv enables the monitoring of trends in norovirus strains associated childhood AGE throughout the world on a near real-time basis.

Detection of Norovirus Variant GII.4 Hong Kong in Asia and Europe, 2017-2019.

We report a new norovirus GII.4 variant, GII.4 Hong Kong, with low-level circulation in 4 Eurasia countries since mid-2017. Amino acid substitutions in key residues on the virus capsid associated with the emergence of pandemic noroviruses suggest that GII.4 Hong Kong has the potential to become the next pandemic variant.

Molecular characterization of rotavirus diarrhea among children aged under five years in the Philippines, 2013-2015.

With the availability of new and existing rotavirus vaccines, credible and reliable data on burden of rotavirus-associated disease are needed to enable evidence-based decision making regarding the introduction of rotavirus vaccines. The national rotavirus surveillance program in the Philippines, a sentinel-based surveillance, was established in 2012 to determine the proportion of laboratory-confirmed rotavirus cases among children under five years with acute gastroenteritis and to describe the geographic distribution and molecular epidemiology of rotavirus in the country. During 2013 to 2015, rotavirus infection was the cause of acute gastroenteritis among children under five years admitted to hospitals or evaluated in emergency rooms, constituting more than one-third of gastroenteritis hospitalizations at the sentinel site hospitals. The predominant genotype observed was G1P[8]. Although a rotavirus surveillance network has been established, findings suggest the need to strengthen the network in the country and to continue monitoring prevalent rotavirus strains to help identify the possible emergence of new strains.

Effectiveness of monovalent rotavirus vaccine in the Philippines.

Rotavirus (RV) is an important cause of diarrheal disease particularly in children aged under 5 years. Monovalent RV vaccine (RVV) was selectively introduced in 2012 in the Philippines and in July 2014 was introduced in the public health program of a province. Two RVV doses are recommended at 6 and 10 weeks of age. We conducted a test negative case-control evaluation to assess the effectiveness of RVV when given in a routine public health program in the Philippines. From September 2014 to August 2017, 967 children aged <5 years were hospitalized with diarrhea and of these, we enrolled 600 who were eligible to have received RVV and provided stool specimens for testing. Among children ≥8 months of age who were age-eligible to have received RVV, at least one dose of RVV had an adjusted vaccine effectiveness (VE) against RV hospitalization of 60% (95% confidence interval, CI: 24%, 79%), and against severe rotavirus diarrhea, VE was 64% (95% CI: 11%, 85%). These findings support the introduction of RVV into routine public health use in the Philippines. However, other factors such as costs, cost-effectiveness and operational issues must be considered prior to adoption of the vaccine into the countries' public immunization program.

Hepatitis B seroprevalence among 5 to 6 years old children in the Philippines born prior to routine hepatitis B vaccination at birth.

To assess the prevalence of hepatitis B in the Philippines, we conducted a cross-sectional study among 5 to 6 year old children born in 2007-2008, when the birth dose started to be implemented in the country. The study was conducted from 25 July to 22 October 2013 in 24 provinces and used a 3-stage cluster design and probability-proportional to size sampling. Blood was obtained and sera were tested for hepatitis B surface antigen (HBsAg). The survey included 2,769 children, of whom 26% received a timely birth dose (within 24 hours of birth) and 89% received 3 doses of the hepatitis B vaccine. Due to problems in the initial testing algorithm, only 2,407 sera were available for HBsAg testing, 20 (weighted%, 0.86%) were HBsAg positive. By immunization card and recall, among HBsAg positive children, 2 (weighted%, 20%) received a timely birth dose while 17 (weighted%, 85%) received 3 doses of the hepatitis B vaccine. The seroprevalence of HBsAg that we detected was lower than expected. However, there were several limitations in the field and in the laboratory that may have affected the representativeness of the results. Follow up studies need to be conducted to validate these results.

Impact of rotavirus vaccine on diarrheal hospitalization and outpatient consultations in the Philippines: First evidence from a middle-income Asian country.

BACKGROUND: Monovalent rotavirus (RV) vaccine was introduced in the Philippines in a phased manner beginning in 2012. To assess the impact of RV vaccine, we conducted a retrospective review of diarrheal admissions in two hospitals. METHODS: Records of physician-diagnosed diarrheal admissions were reviewed in D.O. Plaza Hospital (DOPH) from 2009 to 2016 in Agusan del Sur where RV vaccine was introduced in the immunization program; and in Cotabato Regional Medical Center (CRMC) from 2011 to 2016 in a region where the vaccine was not introduced. Reports from consultations in public health clinics in Agusan Del Sur and RV vaccine coverage were obtained. RESULTS: All-cause diarrheal admissions among children <5 years old in DOPH declined from 2013 to 2016 following RV vaccine introduction in 2012. Using the 2009-2011 mean number of hospitalizations as baseline (X‾ = 1,141), the reductions were 28% (n = 821), 56% (n = 507), 63% (n = 417) and 59% (n = 466) in 2013, 2014, 2015 and 2016, respectively. In comparison, no substantial declines in diarrheal hospitalizations were seen in CRMC from 2011 to 2016. A declining trend was also seen in outpatient consultations in Agusan del Sur following RV vaccine introduction with declines of 27% (n = 2,333), 33% (n = 2,143), 45% (n = 1,764) and 67% (n = 1,059) in 2013, 2014, 2015 and 2016. From September 2012 to December 2016, the 1 and 2-dose RV vaccine coverage gradually increased from 5% and 4% in 2012 to 92% and 88% in 2015, but decreased in 2016 to 53% and 52%, respectively. DISCUSSION: RV vaccine introduction was associated with a substantial decline in diarrheal hospitalizations and outpatient consultations for diarrhea in Agusan del Sur, Philippines.