Background The coronavirus disease (COVID-19) pandemic is an important health crisis worldwide. Several strategies were implemented to combat COVID-19, including wearing masks, hand hygiene, and social distancing. The impact of these strategies on COVID-19 and other viral infections remains largely unclear. Objective We aim to investigate the impact of implemented infectious control strategies on the incidences of influenza, enterovirus infection, and all-cause pneumonia during the COVID-19 pandemic. Methods We utilized the electronic database of the Taiwan National Infectious Disease Statistics System and extracted incidences of COVID-19, influenza virus, enterovirus, and all-cause pneumonia. We compared the incidences of these diseases from week 45 of 2016 to week 21 of 2020 and performed linear regression analyses. Results The first case of COVID-19 in Taiwan was reported in late January 2020 (week 4). Infectious control strategies have been promoted since late January. The influenza virus usually peaks in winter and decreases around week 14. However, a significant decrease in influenza was observed after week 6 of 2020. Regression analyses produced the following results: 2017, R2=0.037; 2018, R2=0.021; 2019, R2=0.046; and 2020, R2=0.599. A dramatic decrease in all-cause pneumonia was also reported (R2 values for 2017-2020 were 0.435, 0.098, 0.352, and 0.82, respectively). Enterovirus had increased by week 18 in 2017-2019, but this was not observed in 2020. Conclusions Using this national epidemiological database, we found a significant decrease in cases of influenza, enterovirus, and all-cause pneumonia during the COVID-19 pandemic. Wearing masks, hand hygiene, and social distancing may contribute not only to the prevention of COVID-19 but also to the decline of other respiratory infectious diseases. Further studies are warranted to elucidate the causal relationship.

ObjectiveIncreased incidence of adenovirus infection in children was noticed since September 2010 in Taiwan and severe cases requiring intensive care were noted later. We did this study to find the clinical characteristics and risk factors associated with severe adenovirus infection.Patients and MethodsWe collected cases of severe adenovirus infection between November 2010 and June 2011 to analyze their clinical characteristics in two medical centers in northern Taiwan. Severe adenovirus infection was defined as laboratory-confirmed adenovirus cases with required intensive care. Hexon gene sequencing was performed for molecular genotyping.Results45 patients were included, 22 cases (49%) were infected with serotype 7, 19 (42%) with serotype 3, and 4 with serotype 2. The median age (range) was 2.75 years (0.08–15.43 years); 87% were below 5 years. Male to female ratio was 1.65 (28 to 17). Of these patients, 56% had underlying neurological diseases, 50% experienced fever higher than 40°C and 69% suffered fever longer than one week. The clinical diagnosis included pneumonia in 40 (89%) patients, bronchopneumonia in 5 (11%), and encephalitis in 7 (16%). At least 22 patients had pleural effusion. They had complications of respiratory failure (53%), acute respiratory distress syndrome (24%), hypotension (40%), and 6 (13%) patients needed extracorporeal membranous oxygenation. Ten (22%) patients died, all with underlying major systemic diseases and 7 (70%) infected with serotype 7.ConclusionsAdenovirus serotype 7 and 3 can cause severe disease–even death–in children, especially those with underlying neurological diseases. Patients infected with adenovirus serotype 7 tended to have a higher case-fatality rate.

Adenovirus type 7 caused a high proportion of severe infections.

Coronavirus disease 2019 (COVID-19) patients exhibited protean clinical manifestations. Olfactory and gustatory abnormalities (anosmia and ageusia) were observed in COVID-19 patients, but the reported prevalence varied. In this systematic review, the prevalence of olfactory and gustatory abnormalities (OGA) was evaluated in laboratory-confirmed COVID-19 patients. On 8 May 2020, 14,506 articles were screened, while 12 of them were enrolled. A total of 1739 COVID-19 patients were analyzed, with a wide range of prevalence observed (5.6–94%). The pooled prevalence was 48.5% with high heterogeneity (I2, 98.8%; p < 0.0001). In total, 15.5% had OGA as their first symptom (I2, 22.6%; p = 0.27) among the patients analyzed. Contradictory to COVID-19 negative controls, patients with COVID-19 had a higher risk of OGA (odds ratio, 5.3; I2, 66.5%; p = 0.03). In conclusion, approximately half of COVID-19 patients had OGA, and one-seventh of them had OGA as their initial symptoms. OGA were cardinal symptoms of COVID-19, which may serve as clues for early diagnosis. Diagnostic testing for SARS-CoV-2 was suggested in patients with OGA during the COVID-19 pandemic to ensure timely diagnosis and appropriate quarantine.

Background: MVC-COV1901 is a subunit SARS-CoV-2 vaccine based on the prefusion spike protein S-2P and adjuvanted with CpG 1018 and aluminum hydroxide. Although MVC-COV1901 has been licensed for emergency use for adults in Taiwan, the safety and immunogenicity of MVC-COV1901 in adolescents remained unknown. As young people play an important role in SARS-CoV-2 transmission and epidemiology, a vaccine approved for adolescents and eventually, children, will be important in mitigating the COVID-19 pandemic. Methods: This study is a prospective, double-blind, multi-center phase 2 trial evaluating the safety, tolerability and immunogenicity of two doses of the SARS-CoV-2 vaccine MVC-COV1901 in adolescents. Healthy adolescents from age of 12 to 17 years were recruited and randomly assigned (6:1) to receive two intramuscular doses of either MVC-COV1901 or placebo at 28 days apart. The primary outcomes were safety and immunogenicity from the day of first vaccination (Day 1) to 28 days after the second vaccination (Day 57), and immunogenicity of MVC COV1901 in adolescents as compared to young adult vaccinees in terms of neutralizing antibody titers and seroconversion rate. The secondary outcomes were safety and immunogenicity of MVC-COV1901 as compared to placebo in adolescents in terms of immunoglobulin titers and neutralizing antibody titers over the study period. Results: Between July 21, 2021 and December 22, 2021, a total of 399 adolescent participants were included for safety evaluation after enrollment to receive at least one dose of either MVC-COV1901 (N=341) or placebo (N=58). Of these, 334 and 46 participants went on to receive two doses of either MVC-COV1901 or placebo, respectively, and were included in the per protocol set (PPS) for immunogenicity analysis. Adverse events were mostly mild and were similar in MVC-COV1901 and placebo groups. The most commonly reported adverse events were pain/tenderness and malaise/fatigue. All immunogenicity endpoints in the adolescent group were non-inferior to the endpoints seen in the young adult and placebo groups. Conclusions: The safety and immunogenicity data presented here showed that MVC-COV1901 has similar safety profile and non-inferior immunogenicity in adolescents compared to young adults.