Antibody Response after a Booster COVID-19 Vaccine Mixing in Vietnam.

BACKGROUND: The booster vaccine is essential for maintaining the antibody against the severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) virus. This study sought to evaluate the antibody response after booster coronavirus disease 2019 (COVID-19) vaccines and compare the immunogenic by different vaccine combination strategies. METHODS: A cross-sectional study in Hanoi, Vietnam was conducted on 679 adult participants who received two doses of vaccines with any combination of AstraZeneca, Pfizer, and Moderna during the COVID-19 vaccination campaign in 2021. The SARS-CoV-2 S1/S2 Immunoglobulin G (IgG) antibody concentrations were measured by the LIAISON SARS-CoV-2 S1/S2 IgG and presented as arbitrary units. RESULTS: We found that the median (interquartile range (IQR)) of IgG level among those who completed two doses of Moderna and Pfizer was 484.55 (284.80) AU/mL and 349.00 (362.50) AU/mL, respectively. Meanwhile, the counterpart of AstraZeneca was 110.00 (128.10) AU/mL. Mixing two doses of AstraZeneca-Pfizer has higher odds of having high IgG level than two doses of Pfizer (Odds Ratios (OR) = 2.94, 95% Confidence Intervals (CI): 1.57-5.51), AstraZeneca (OR = 28.50, 95% CI: 15.00-54.14). CONCLUSIONS: We found that the matching two doses of mRNA vaccines are more immunogenic as compared to the DNA vector vaccines. Furthermore, mixing AstraZeneca-Pfizer has higher antibody quantities as compared to matching vaccines, while lower the rate of advert events.

Antibiotic resistance of Streptococcus pneumoniae in Vietnamese children with severe pneumonia: a cross-sectional study.

Background: Streptococcus pneumoniae is the most common bacterium that causes community-acquired pneumonia (CAP) in children. The rate of S. pneumoniae resistance to antibiotics is increasing, particularly in patients with severe CAP. Therefore, the level of antibiotic resistance of S. pneumoniae causing severe CAP in Vietnamese children requires regular monitoring. Methods: This was a cross-sectional descriptive study. Nasopharyngeal aspiration specimens from children were cultured, isolated, and examined for S. pneumoniae. Bacterial strains were assessed for antimicrobial susceptibility, and the minimum inhibitory concentration (MIC) was determined. Results: Eighty-nine strains of S. pneumoniae were isolated from 239 children with severe CAP. The majority of isolates were completely non-susceptible to penicillin (1.1% intermediate, 98.9% resistant) and highly resistant to erythromycin (96.6%) and clarithromycin (88.8%); the rate of resistance to ceftriaxone was 16.9%, with the proportion of intermediate resistance at 46.0%; 100% of strains were susceptible to vancomycin and linezolid. For most antibiotics, MIC50 and MIC90 were equal to the resistance threshold according to the Clinical and Laboratory Standards Institute 2021; penicillin had an eight-fold increase in MIC90 (64 mg/L) and ceftriaxone had a 1.5-fold increase in MIC90 (6 mg/L). Conclusion: Streptococcus pneumoniae isolates described in this study were resistant to many antibiotics. Penicillin should not be the first-line antibiotic of choice, and ceftriaxone at an enhanced dose should be used instead.

Country data on AMR in Vietnam in the context of community-acquired respiratory tract infections: links between antibiotic susceptibility, local and international antibiotic prescribing guidelines, access to medicines and clinical outcome.

BACKGROUND: Antimicrobial resistance (AMR) is one of the biggest threats to global public health. Selection of resistant bacteria is driven by inappropriate use of antibiotics, amongst other factors. COVID-19 may have exacerbated AMR due to unnecessary antibiotic prescribing. Country-level knowledge is needed to understand options for action. OBJECTIVES: To review the current situation with respect to AMR in Vietnam and initiatives addressing it. Identifying areas where more information is required will provide a call to action to minimize any further rises in AMR within Vietnam and improve patient outcomes. METHODS: National initiatives to address AMR in Vietnam, antibiotic use and prescribing, and availability of susceptibility data, in particular for the key community-acquired respiratory tract infection (CA-RTI) pathogens Streptococcus pneumoniae and Haemophilus influenzae, were identified. National and international antibiotic prescribing guidelines for CA-RTIs (community-acquired pneumonia, acute otitis media and acute bacterial rhinosinusitis) commonly used locally were also reviewed, plus local antibiotic availability. Insights from clinicians in Vietnam were sought to contextualize this information. CONCLUSIONS: In Vietnam there have been some initiatives addressing AMR; Vietnam was the first country in the Western Pacific Region to develop a national action plan to combat AMR, which according to the WHO is being implemented. Vietnam also has one of the highest rates of AMR in Asia due, in part, to the overuse of antimicrobial drugs, both in the animal health sector and in humans in both hospitals and the community. In addition, despite a 2005 law requiring antibiotic prescription, there is unrestricted access to over-the-counter antibiotics. Several global surveillance studies provide antibiotic susceptibility data for CA-RTI pathogens in Vietnam including Survey of Antibiotic Resistance (SOAR) and SENTRY (small isolate numbers only). For management of the common CA-RTIs in Vietnam there are several country-specific local antibiotic prescribing guidelines and in addition, there is a range of international guidelines referred to, but these may have been created based on pathogen resistance patterns that might be very different to those in Vietnam. Expert clinician opinion confirms the high resistance rates among common respiratory pathogens. A more standardized inclusive approach in developing local guidelines, using up-to-date surveillance data of isolates from community-acquired infections in Vietnam, could make management guideline use more locally relevant for clinicians. This would pave the way for a higher level of appropriate antibiotic prescribing and improved adherence. This would, in turn, potentially limit AMR development and improve clinical outcomes for patients.

Study on the co-infection of children with severe community-acquired pneumonia.

BACKGROUD: Pneumonia is one of the leading causes of death in children under 5 years old. Viruses have historically been the most common cause of community-acquired pneumonia in children. Co-infections in severe pneumonia are more concern by clinicians. METHOD: It was a perspective and descriptive study. Real-time polymerase chain reaction (RT-PCR) is a modern test that was used to detect many new pathogens, including microbiological co-infections. RT-PCR technique was used in this study to investigate the causes of severe pneumonia. RESULTS: Through the analysis of nasopharyngeal aspiration samples from 95 children with severe community-acquired pneumonia, the positive RT-PCR rate was 90.5%. Viral-bacterial co-infection accounted for the highest proportion (43.1%), followed by bacterial co-infection (33.7%), viral infection (7.4%), bacterial infection (6.3%) and the remaining 9.5% was unknown. In the co-infections groups, the five main bacteria species detected by PCR were Streptococcus pneumoniae, Haemophilus influenzae, MRSA, Moraxella catarrhalis and Mycoplasma pneumoniae. CONCLUSION: Antibiotic treatment should focus on detected microbes in cases of severe pneumonia for having a good result.

Changing trends in antimicrobial resistance and serotypes of Streptococcus pneumoniae isolates in Asian countries: an Asian Network for Surveillance of Resistant Pathogens (ANSORP) study.

Antimicrobial resistance in Streptococcus pneumoniae remains a serious concern worldwide, particularly in Asian countries, despite the introduction of heptavalent pneumococcal conjugate vaccine (PCV7). The Asian Network for Surveillance of Resistant Pathogens (ANSORP) performed a prospective surveillance study of 2,184 S. pneumoniae isolates collected from patients with pneumococcal infections from 60 hospitals in 11 Asian countries from 2008 to 2009. Among nonmeningeal isolates, the prevalence rate of penicillin-nonsusceptible pneumococci (MIC, ≥ 4 µg/ml) was 4.6% and penicillin resistance (MIC, ≥ 8 µg/ml) was extremely rare (0.7%). Resistance to erythromycin was very prevalent in the region (72.7%); the highest rates were in China (96.4%), Taiwan (84.9%), and Vietnam (80.7%). Multidrug resistance (MDR) was observed in 59.3% of isolates from Asian countries. Major serotypes were 19F (23.5%), 23F (10.0%), 19A (8.2%), 14 (7.3%), and 6B (7.3%). Overall, 52.5% of isolates showed PCV7 serotypes, ranging from 16.1% in Philippines to 75.1% in Vietnam. Serotypes 19A (8.2%), 3 (6.2%), and 6A (4.2%) were the most prominent non-PCV7 serotypes in the Asian region. Among isolates with serotype 19A, 86.0% and 79.8% showed erythromycin resistance and MDR, respectively. The most remarkable findings about the epidemiology of S. pneumoniae in Asian countries after the introduction of PCV7 were the high prevalence of macrolide resistance and MDR and distinctive increases in serotype 19A.