Long-term side effects of vaccines?
Long-term Side Effects of COVID-19 Vaccine? What We Know.
[Children’s Hospital of Philadelphia feature.] The history of vaccines shows that delayed effects following vaccination can occur. But when they do, these effects tend to happen within two months of vaccination [for oral polio, yellow fever, influenza, MMR, and adenovirus Covid vaccines]. [See also 2:39 video with Dr. Paul Offit.]
Effectiveness of the CoronaVac vaccine in the elderly population during a P.1 variant-associated epidemic of COVID-19 in Brazil: A test-negative case-control study
[Sinovac. Preprint.] We selected 7,950 matched pairs with a mean age of 76 years from 26,433 COVID-19 cases and 17,622 test-negative controls. Adjusted vaccine effectiveness was 18.2% (95% CI, 0.0 to 33.2) and 41.6% (95% CI, 26.9 to 53.3) in the period 0-13 and ≥14 days, respectively, after the 2nd dose. Administration of a single vaccine dose was not associated with reduced odds of COVID-19. Vaccine effectiveness ≥14 days after the 2nd dose declined with increasing age and was 61.8% (95% CI 34.8 to 77.7), 48.9% (95% CI 23.3 to 66.0) and 28.0% (95% CI 0.6 to 47.9) among individuals 70-74, 75-79 and ≥80 years of age, respectively (pinteraction = 0.05). CoronaVac was 42% effective in the real-world setting of extensive P.1 transmission, but significant protection was not observed until completion of the two-dose regimen and vaccine effectiveness declined with increasing age.
Comparative Household Secondary Attack Rates associated with B.1.1.7, B.1.351, and P.1 SARS-CoV-2 Variants
[Preprint.] We identified individuals with confirmed SARS-CoV-2 infection in Canada’s largest province of Ontario. We identified 26,888 index household cases during the study period. Among these, 7,555 (28%) were wild-type, 17,058 (63%) were B.1.1.7, 1674 (6%) were B.1.351 or P.1, and 601 (2%) were non-VOC mutants (Table 1). The secondary attack rates, according to index case variant were as follows: 20.2% (wild-type), 25.1% (B.1.1.7), 27.2% (B.1.351 or P.1), and 23.3% (non-VOC mutants). In adjusted analyses, we found that B.1.1.7, B.1.351, and P.1 index cases had the highest transmissibility (presumptive B.1.1.7 ORadjusted=1.49, 95%CI 1.36, 1.64; presumptive B.1.351 or P.1 ORadjusted=1.60, 95%CI 1.37, 1.87). Substantially higher transmissibility associated with variants will make control of SARS-CoV-2 more difficult.
COVID-19 transmission in group living environments and households
total of 4550 individuals with a history of recent contact with patients at different places (dormitory/home/outside the residences) and levels (close/lower-risk) were tested for SARS-CoV-2 viral RNA using a nasopharyngeal swab test between July 2020 and May 2021. The test-positive rate was highest in individuals who had contact in dormitories (27.5%), but the rates were largely different between dormitories with different infrastructural or lifestyle features and infection control measures among residents. With appropriate infection control measures, the secondary transmission risk in dormitories was adequately suppressed. The household transmission rate (12.6%) was as high as that of close contact outside the residences (11.3%) and accounted for > 60% of the current rate of COVID-19 transmission among non-adults. In conclusion, a group living environment is a significant risk factor of secondary transmission.
The missing season: The impacts of the COVID-19 pandemic on influenza
The 2020 Southern Hemisphere and 2020–2021 Northern Hemisphere influenza seasons were entirely suppressed. The potential causes and impacts of this drastic public health shift are highly uncertain. One potential expla-nation for this pattern is viral competition between SARS-CoV-2 and influenza. Another potential explanation for the decrease in the 2020 influenza burden is increased influenza vaccination. While viral competition and increased vaccination may have contributed, we propose that the most influential process in sup-pressing the influenza epidemic of 2020–2021 were the significant behavioral interventions in place due to the COVID-19 pandemic.