Centers for Disease Control and Prevention (CDC) recommended that any individuals who develop myocarditis/pericarditis after a dose of an mRNA COVID-19 vaccine should defer receiving a subsequent dose until additional safety data are available.
On 9th November, 2021, the CDC allows mix and match of booster shots in USA.
National Advisory Committee on Immunization (NACI) recommended boosters for other high-risk groups, including people 70 years of age and older and front-line health care workers who had a short period of time between their first two shots.
NACI also recommended boosters for people who received two doses of the Astra Zeneca vaccine, as the mRNA vaccines appear to offer better protection.
On 4th November, 2021, the United Kingdom became the first country to approve Pfizer’s competitorOK competitor Merck's COVID-19 pill, which is already under review at the Food and Drug Administration (FDA) after showing strong initial results. Other antivirals are under consideration including an agent from Pfizer (Paxlovid). While promising, caution should be taken with interpreting data from oral antivirals as currently, no published data exist and much conclusions are drawn off grey literature .
India’s Covaxin covid 19 vaccine by Bharat Biotech reported a vaccine effectiveness of 77.8% from a clinical trial. , 2021, a CDC reported vaccine efficacy of 90.9% with primary data from one phase II/III clinical trial in preventing symptomatic, laboratory-confirmed COVID-19 in children aged 5–11 years with or without evidence of previous SARS-CoV-2 infection.
November 2, 2021
October 21st, 2021 Pfizer Inc. and BioNTech announced results from a Phase 3 randomized, controlled trial evaluating the efficacy and safety of a 30-µg booster dose of the Pfizer-BioNTech COVID-19 with a relative vaccine efficacy of 95.6%.
On 21st October, 2021, the advisory panel for the Centers for Disease Control and Prevention (CDC) said people who received Moderna and Johnson & Johnson (J&J) COVID-19 vaccines should receive a booster dose, and should continue with the original vaccine they recieved.
NACI’s latest guidelines suggest provinces should offer boosters to Canadians who received two doses of the Oxford-AstraZeneca vaccine or one dose of the Johnson & Johnson vaccine.
The US Food and Drug Administration (FDA) vaccine advisory group on 26th October 2021 approved the emergency use of the Pfizer-BioNTech COVID-19 vaccine for children ages 5 to 11 at a reduced dosage from the stanard dosing available for those over 12.
Therapeutic Goods Administration (Australia) has provisionally approved a third dose of the Pfizer (Comirnaty) vaccine for individuals 18 years or older. Pfizer (Comirnaty) is recommended as a single booster dose, irrespective of the primary COVID-19 vaccine used.
On 29th October, 2021, NACI issued new guidance "strongly" recommending booster shots for seniors 80 and older.
A survey at University of Oxford, UK, found that social media played a part in children aged 9 to 18 being more undecided than their older counterparts.
A report by the CDC found that the effectiveness of 2 doses of Pfizer-BioNTech vaccine against COVID-19 hospitalization was 93% during the period of B.1.617.2 (Delta) variant dominance among children and adolescents aged 12–18 years.
In October, WHO released a consensus definition of post COVID-19 condition that includes 12 domains. This development should lead to better standardization of reporting and contribute to more precise prevalence estimates and better understanding of associated risk factors.
The effects of Variants of Concern (VoC) and COVID vaccination on progression of Long COVID symptoms remains unclear.
Risk factors for developing Long COVID symptoms were similar but limited evidence suggests that pre-pandemic psychological distress and poor general health were associated with developing persistent symptoms. Evidence is too limited to determine whether vaccination reduces the risk of developing Long COVID among persons with breakthrough infections.
Given the protean manifestations of Long COVID symptoms, the underlying causes are likely multifactorial; however, strong evidence to substantiate the theories of causation remains limited.
Research related to longer-term consequences of SARS CoV-2 infections in pediatric populations is growing but remains limited.
March 15, 2021
There is a lack of consensus around the clinical definition of Long COVID which in turn causes challenges with understanding the incidence and prevalence as well as the potential impact for the health care system
Information about the natural history of Long COVID is incomplete but limited evidence suggests that the immune response trajectories differ for those with few or no symptoms compared to those with severe disease. Individuals with severe disease are more likely to exhibit immunological marker abnormalities but anyone can experience functional limitations.
The mechanisms underlying the development of persistent symptoms in Long COVID remain an enigma. Despite multiple theories, there is little empirical evidence for specific immunological and or biochemical abnormalities in samples of individuals with symptoms consistent with Long COVID.
Risk factors for Long COVID include female gender, older age, higher body mass index, pre-existing asthma and the number of symptoms.
Few studies explored the short-term impact of Long COVID on health care utilization patterns and found a higher impact for those with severe disease compared with mild disease.
Williams-Roberts, H; Groot, G; Mueller, M; Dalidowicz, M. Long COVID: What does it mean for the healthcare system and programs? 2021 Oct 29. Document no.: EOC021901v2 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2021. 14 p. (CEST rapid review report).
Long COVID-19 is likely to increase healthcare demands across the health system, including emergency departments, hospital admissions, primary care visits, specialists appointments, and home care and rehabilitation services.
The clinical care burden of long COVID-19 is the greatest in the first 3 months after testing and is likely to place the greatest demand on primary care services.
Patients with severe COVID-19 illness are more likely to place longer-term demands (4-6 months) on specialist care due to respiratory, circulatory, endocrine, metabolic, psychiatric and unspecified conditions.
McLean, M; Williams-Roberts, H; Reeder, B; Howell-Spooner, B; Ellsworth, C. What are long COVID's demands on the healthcare system, and its severity of the illness? 2021 Jul 12, Document no.: EPM210602 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2021. 23 p. (CEST rapid review report).
The frequency of Long COVID symptoms varies widely across studies based on populations studied, duration of follow up and methods of assessment of symptoms.
It is estimated that 1 in 50 persons experience Long COVID symptoms after 12 weeks; however, higher estimates up to 80% have been reported in studies with a greater proportion of persons who were previously hospitalized. A recent study of a mixed cohort of 96 persons found that only 22.9% had no symptoms at 12 months post diagnosis.
A wide range of symptoms affecting multiple organ systems has been reported. For many persons symptoms improve over time while others experience persistent and/or new symptoms. Among studies with the longest duration of follow up, the most frequently reported symptoms included fatigue (up to 65%), dyspnea (up to 50%), headache (up to 45%), anosmia/ageusia (up to 25%), cognitive memory/concentration (up to 39.6%) and sleep disorders (up to 26%).
Few studies estimated the duration of symptoms with estimates ranging from 2.2% for 6 months and 27% for 7-9 months.
The mechanism(s) leading to Long COVID remain unclear but those experiencing post acute sequelae tend to be older, have a greater number of symptoms during the acute phase of illness or manifest specific symptoms and live with multiple comorbid conditions such as obesity.
The lack of consensus on a definition of Long COVID contributes to marked variations in robust prevalence estimates.
Williams-Roberts, H; Groot, G; Reeder, B; Howell-Spooner, B; Ellsworth, C. What is the incidence and duration of Long COVID cases? 2021 Jul 09, Document no.: EPM210601 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2021. 19 p. (CEST rapid review report).