Burden of Influenza-Associated Respiratory Hospitalizations, Vietnam, 2014-2016.

Influenza burden estimates are essential to informing prevention and control policies. To complement recent influenza vaccine production capacity in Vietnam, we used acute respiratory infection (ARI) hospitalization data, severe acute respiratory infection (SARI) surveillance data, and provincial population data from 4 provinces representing Vietnam's major regions during 2014-2016 to calculate provincial and national influenza-associated ARI and SARI hospitalization rates. We determined the proportion of ARI admissions meeting the World Health Organization SARI case definition through medical record review. The mean influenza-associated hospitalization rates per 100,000 population were 218 (95% uncertainty interval [UI] 197-238) for ARI and 134 (95% UI 119-149) for SARI. Influenza-associated SARI hospitalization rates per 100,000 population were highest among children <5 years of age (1,123; 95% UI 946-1,301) and adults >65 years of age (207; 95% UI 186-227), underscoring the need for prevention and control measures, such as vaccination, in these at-risk populations.

The First 100 Days of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Control in Vietnam.

BACKGROUND: One hundred days after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in Vietnam on 23 January, 270 cases were confirmed, with no deaths. We describe the control measures used by the government and their relationship with imported and domestically acquired case numbers, with the aim of identifying the measures associated with successful SARS-CoV-2 control. METHODS: Clinical and demographic data on the first 270 SARS-CoV-2 infected cases and the timing and nature of government control measures, including numbers of tests and quarantined individuals, were analyzed. Apple and Google mobility data provided proxies for population movement. Serial intervals were calculated from 33 infector-infectee pairs and used to estimate the proportion of presymptomatic transmission events and time-varying reproduction numbers. RESULTS: A national lockdown was implemented between 1 and 22 April. Around 200 000 people were quarantined and 266 122 reverse transcription polymerase chain reaction (RT-PCR) tests conducted. Population mobility decreased progressively before lockdown. In total, 60% (163/270) of cases were imported; 43% (89/208) of resolved infections remained asymptomatic for the duration of infection. The serial interval was 3.24 days, and 27.5% (95% confidence interval [CI], 15.7%-40.0%) of transmissions occurred presymptomatically. Limited transmission amounted to a maximum reproduction number of 1.15 (95% CI, .·37-2.·36). No community transmission has been detected since 15 April. CONCLUSIONS: Vietnam has controlled SARS-CoV-2 spread through the early introduction of mass communication, meticulous contact tracing with strict quarantine, and international travel restrictions. The value of these interventions is supported by the high proportion of asymptomatic and imported cases, and evidence for substantial presymptomatic transmission.

Transmission of SARS-CoV 2 During Long-Haul Flight.

To assess the role of in-flight transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), we investigated a cluster of cases among passengers on a 10-hour commercial flight. Affected persons were passengers, crew, and their close contacts. We traced 217 passengers and crew to their final destinations and interviewed, tested, and quarantined them. Among the 16 persons in whom SARS-CoV-2 infection was detected, 12 (75%) were passengers seated in business class along with the only symptomatic person (attack rate 62%). Seating proximity was strongly associated with increased infection risk (risk ratio 7.3, 95% CI 1.2-46.2). We found no strong evidence supporting alternative transmission scenarios. In-flight transmission that probably originated from 1 symptomatic passenger caused a large cluster of cases during a long flight. Guidelines for preventing SARS-CoV-2 infection among air passengers should consider individual passengers' risk for infection, the number of passengers traveling, and flight duration.

Plans for Nationwide Serosurveillance Network in Vietnam.

In recent years, serosurveillance has gained momentum as a way of determining disease transmission and immunity in populations, particularly with respect to vaccine-preventable diseases. At the end of 2017, the Oxford University Clinical Research Unit and the National Institute of Hygiene and Epidemiology held a meeting in Vietnam with national policy makers, researchers, and international experts to discuss current seroepidemiologic projects in Vietnam and future needs and plans for nationwide serosurveillance. This report summarizes the meeting and the plans that were discussed to set up nationwide serosurveillance in Vietnam.

Swine influenza viruses in Northern Vietnam in 2013-2014.

Swine are an important intermediate host for emergence of pandemic influenza. Vietnam is the largest swine producer in South East Asia. Systematic virological and serological surveillance of swine influenza viruses was carried out in Northern Vietnam from May 2013 to June 2014 with monthly sampling of pigs in local and large collective slaughterhouses and in a live pig market. Influenza A seroprevalence in the local slaughterhouses and in the large collective slaughterhouse was 48.7% and 29.1%, respectively. Seventy-seven influenza A viruses were isolated, all from the large collective slaughterhouse. Genetic analysis revealed six virus genotypes including H1N1 2009 pandemic (H1N1pdm09) viruses, H1N2 with H1 of human origin, H3N2 and H1N1pdm09 reassortants, and triple-reassortant H3N2 viruses. Phylogenetic analysis of swine and human H1N1pdm09 viruses showed evidence of repeated spill-over from humans to swine rather than the establishment of H1N1pdm09 as long-term distinct lineage in swine. Surveillance at the large collective slaughterhouse proved to be the most efficient, cost-effective, and sustainable method of surveillance for swine influenza viruses in Vietnam.

Human papillomavirus vaccine introduction in Vietnam: formative research findings.

BACKGROUND: Formative research is a useful tool for designing new health interventions. This paper presents key findings from formative research conducted in Vietnam to guide human papillomavirus (HPV) vaccine introduction. METHODS: We explored the sociocultural environment, health system capacity and the policy-making process using a combined quantitative and qualitative methodology. Data collection was done through literature review, in-depth interviews, focus group discussions, observation checklists and a structured questionnaire on knowledge, attitudes and practices. Populations of interest included 11- to 14-year-old girls, their parents, community leaders, teachers, health workers, health and education officials, and policy-makers at all levels. RESULTS: Although HPV vaccines are new, we found high potential acceptance among parents and girls. HPV vaccine introduction was also favourably supported by health professionals if assurances for system preparedness, e.g. cold chain and human resources, were made. There were no significant barriers from the policy perspective that would prevent the introduction of a new vaccine. However, several concerns related to this new vaccine would need to be adequately addressed before implementation. CONCLUSION: Our findings provide options for potential vaccine delivery strategies, appropriate communication strategies and targeted advocacy strategies to introduce HPV vaccines in the Vietnamese context.