Vaccine effectiveness against infection with the Delta (B.1.617.2) variant, Norway, April to August 2021.

Some variants of SARS-CoV-2 are associated with increased transmissibility, increased disease severity or decreased vaccine effectiveness (VE). In this population-based cohort study (n = 4,204,859), the Delta variant was identified in 5,430 (0.13%) individuals, of whom 84 were admitted to hospital. VE against laboratory confirmed infection with the Delta variant was 22.4% among partly vaccinated (95% confidence interval (CI): 17.0-27.4) and 64.6% (95% CI: 60.6-68.2) among fully vaccinated individuals, compared with 54.5% (95% CI: 50.4-58.3) and 84.4% (95%CI: 81.8-86.5) against the Alpha variant.

Severe acute respiratory syndrome coronavirus 2 prevalence in 1170 asymptomatic Norwegian conscripts.

BACKGROUND: Accurate estimates of SARS-CoV-2 infection in different population groups are important for the health authorities. In Norway, public infection control measures have successfully curbed the pandemic. However, military training and service are incompatible with these measures; therefore extended infection control measures were implemented in the Norwegian Armed Forces. We aimed to describe these measures, discuss their value, and investigate the polymerase chain reaction (PCR) prevalence and seroprevalence of SARS-CoV-2, as well as changes in antibody titer levels over the 6-week military training period in a young, asymptomatic population of conscripts. METHODS: In April 2020, 1170 healthy conscripts (median age 20 years) enrolled in military training. Extended infection control measures included a pre-enrollment telephone interview, self-imposed quarantine, questionnaires, and serial SARS-CoV-2 testing. At enrollment, questionnaires were used to collect information on symptoms, and SARS-CoV-2 rapid antibody testing was conducted. Serial SARS-CoV-2 PCR and serology testing were used to estimate the prevalence of confirmed SARS-CoV-2 and monitor titer levels at enrollment, and 3 and 6 weeks thereafter. RESULTS: At enrollment, only 0.2% of conscripts were SARS-CoV-2 PCR-positive, and seroprevalence was 0.6%. Serological titer levels increased nearly 5-fold over the 6-week observation period. Eighteen conscripts reported mild respiratory symptoms during the 2 weeks prior to enrollment (all were PCR-negative; one was serology-positive), whereas 17 conscripts reported respiratory symptoms and nine had fever at enrollment (all were PCR- and serology-negative). CONCLUSIONS: The prevalence of SARS-CoV-2 was less than 1% in our sample of healthy Norwegian conscripts. Testing of asymptomatic conscripts seems of no value in times of low COVID-19 prevalence. SARS-CoV-2 antibody titer levels increased substantially over time in conscripts with mild symptoms.

Asymptomatic COVID-19 with ambiguous test results. / Asymptomatisk covid-19 med usikre testresultater.

BACKGROUND: Testing for SARS-CoV-2 using polymerase chain reaction (PCR) and SARS-CoV-2 antibody tests is a significant part of the effort to combat the COVID-19 pandemic. Mass testing of healthy individuals raises several issues, however, and the results can be challenging to interpret. CASE PRESENTATION: A healthy 19-year-old man entered the military after two weeks of quarantine. The recruit had no respiratory symptoms or fever before, during or after his enrolment, and no history of SARS-CoV-2 exposure. At enrolment, he had a positive rapid test and a venous blood sample showed antibodies against SARS-CoV-2. PCR tests of specimens obtained from the upper respiratory tract were negative at enrolment and at week three, but were positive at week six. INTERPRETATION: The overall assessment of all the tests indicates a probable asymptomatic infection. This case report illustrates the challenge of interpreting screening results in asymptomatic individuals.

Status of COVID-19 vaccine development. / Status for vaksineutvikling mot covid-19.

The pandemic caused by SARS-CoV-2 has created a global humanitarian and economic crisis for which there is currently no solution in sight. Much hope has therefore been pinned on a vaccine that can protect against the disease COVID-19. As of August 2020, the World Health Organization has registered 173 vaccine candidates as being in development. Six candidates have entered phase 3 trials, and the first results from these are expected in the autumn.