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9th August 2022
COVID-19 vaccination provides individuals with a reduced risk of experiencing an acute myocardial infarction or ischaemic stroke after becoming infected with the virus according to the findings of a study by Korean researchers.
It has now become recognised that following an acute infection with COVID-19, beyond the first 30 days, individuals with COVID-19 have an increased risk of cardiovascular disease and which includes cerebrovascular disorders, dysrhythmias, ischaemic and non-ischaemic heart disease, pericarditis, myocarditis, heart failure and thromboembolic disease. While it is clear that a COVID-19 vaccination is safe and offers protection against severe COVID-19, hospitalisation and death against all current variants of concern, what is less clear is whether vaccination is able to reduce the post-infection cardiovascular sequelae.
As a result, for the present study, the Korean researchers undertook a retrospective cohort study and compared the incidence of acute myocardial infarction and ischaemic stroke in those with and without full COVID-19 vaccination. They linked data from the Korean nationwide COVID-19 registry and the National Health Insurance database and included all adults who were diagnosed with COVID-19 between July 2020 and December 2021.
However, the team excluded several patient groups including: individuals whose data showed that they had a cardiovascular event three months before a COVID-19 infection, cases of re-infection with the virus and patients who were vaccinated but hospitalised with the virus for longer than 30 days.
They set the primary outcome of interest as a composite of all hospitalisations for an acute myocardial infarction and ischaemic stroke and which had occurred 31 to 120 days after an individual’s COVID-19 diagnosis. They decided to exclude cardiovascular events within the first 30 days of infection because of the inherent difficulty of differentiating whether the event was related to infection of treatment.
COVID-19 vaccination and cardiovascular outcomes
A total of 231,037 patients were included in the analysis, of whom 62,727 were unvaccinated and with a median age of 42 years (51.5% female). The median age of the vaccinated group was higher (57 years) and had a greater incidence of co-morbidities including diabetes (11.8% vs 7.1%, vaccinated vs unvaccinated) and hypertension (22.1% vs 10.8%). Furthermore, a higher proportion of unvaccinated individuals had severe COVID-19 (3.1% vs 9.8%).
The median period of follow-up was 90 days in the unvaccinated and 84 days in the fully vaccinated group (which was defined as receipt of 2 doses of a vaccine).
The composite outcome occurred in 31 unvaccinated individuals and 74 of those who were fully vaccinated and after adjustment for differences in baseline characteristics, this difference was statistically significant (hazard ratio, HR = 0.42, 95% CI -.29 – 0.62, p < 0.001). This difference was also significant for the individual components of the composite.
The authors concluded that full COVID-19 vaccination was protective against the acute myocardial infarction and an ischaemic stroke that could arise after infection with the virus, compared with individuals who were unvaccinated.
Citation
Kim YE et al. Association Between Vaccination and Acute Myocardial Infarction and Ischemic Stroke After COVID-19 Infection JAMA 2022
12th July 2022
Both overweight and obese patients who have been vaccinated against COVID-19 have a similar degree of protection against severe disease and death as those of a healthy weight according to a large, population-based cohort study by researchers from the UK and Spain.
Since the start of the COVID-19 pandemic, considerable evidence has emerged indicating how obesity is a risk factor for more severe disease. For example, in a 2020 systematic review of 24 retrospective cohort studies, the odds ratio for intensive care unit admission for obese patients was 1.21 and higher still, for invasive mechanical ventilation (OR = 2.05).
With the widespread introduction of COVID-19 vaccines, it is necessary to understand how overweight and obese patients respond to vaccination. This is especially important in light of evidence showing that despite generating a robust serological response, vaccinated obese adults are twice as likely to develop influenza and influenza-like illness compared with healthy weight adults.
Furthermore, another study found that CD4(+) and CD8(+) T cells from overweight and obese individuals expressed lower levels of CD69, CD28, CD40 ligand, and interleukin-12 receptor, compared with healthy weight and which may contribute to the increased morbidity and mortality from H1N1 influenza A virus.
Despite the concern that overweight and obese patients may not produce a satisfactory immune response to vaccination, there are limited data on the association between body mass index (BMI) and COVID-19 vaccine effectiveness and the risk of severe COVID-19 outcomes after vaccination.
Using the QResearch database, in the present study, researchers used an anonymised patient data set derived from over 1,700 general practices in England and collated demographic and clinical data. They linked this information with the NHS Digital database of positive COVID-19 tests, hospital episode statistics and death certificates.
Included patients were adults and who had a BMI measurement recorded in their medical records and which were then categorised as underweight (BMI < 18.5), healthy weight (BMI 18.5 – 24.9), overweight (BMI 25 – 29.9) and obese (BMI > 30). They examined vaccine effectiveness across the different weight categories and set the main outcomes of interest as hospitalisation and death.
Overweight and obese patients and severe COVID-19 outcomes
A total of 9,171,524 individuals with a mean age of 52 years (47% male) were included in the analysis. During the period of study there were 566,461 positive tests for COVID-19, 32,808 COVID-19-related hospital admissions and 14,389 COVID-related deaths.
Across the whole cohort, 19.2% were unvaccinated, 3.1% had at least one dose, 52.6% two doses and 25% three doses. Uptake of two or three vaccine doses was more than 80% among those deemed overweight or obese.
At least 14 days after the second vaccine dose, the likelihood (based on the odds ratio, OR) of a COVID-19-related hospitalisation (compared to those who were unvaccinated) was lowest for those who were either overweight (OR = 0.32, 95% CI 0.30 – 0.34) or obese (OR = 0.32, 95% CI 0.30 – 0.34) which was similar to those with a healthy weight (OR = 0.34).
Among those who were underweight, there was a slightly higher risk of hospitalisation (OR = 0.51, 95% CI 0.41 – 0.63). However, the odds of hospitalisation after a third vaccine dose were significantly less and similar for each of the different BMI categories.
In relation to mortality, there was a similar pattern 14 days after the second dose, e.g., underweight individuals (OR = 0.60), healthy weight (OR = 0.30) with overweight and obese individuals having the same odds ratio (OR = 0.26). Mortality was also significantly lower after the third dose though there was more uncertainty given the lower number of cases.
The authors concluded that both overweight and obese patients appear to be equally well protected against severe COVID-19 outcomes as those of a healthy weight although vaccine effectiveness appeared to be less in those classed as underweight.
Citation
Piernas C et al. Associations of BMI with COVID-19 vaccine uptake, vaccine effectiveness, and risk of severe COVID-19 outcomes after vaccination in England: a population-based cohort study Lancet Diabetes Endocrinol 2022
4th July 2022
The effectiveness of the anti-viral drug paxlovid in preventing the progression of COVID-19 remains even in those who have been adequately vaccinated against the virus according to the results of a real-world study by Israeli researchers.
Paxlovid consists of nirmatrelivir, a protease inhibitor against COVID-19 and ritonavir, which reduces the in vivo metabolism of nirmatrelivir. The published data for the drug (the EPIC-HR trial) suggested that treatment of symptomatic COVID-19 in patients at risk of progression to severe disease, results in an 89% lower risk compared to placebo.
Nevertheless, the study was undertaken before omicron became the main circulating variant and therefore the generalisability of the study’s findings are potentially limited.
Consequently, for the present study, the Israeli team decided to undertake a large, retrospective cohort study of high-risk COVID-19 patients, to assess the effectiveness of paxlovid at preventing progression to severe COVID-19 and subsequent death during the time when omicron was the predominant strain.
Using a large, national health service database, the researchers identified all adults (18 years and over) who tested positive for COVID-19 but restricted the search to those who would be suitable candidates for treatment with paxlovid, i.e., those who were older than 60 years, with a body mass index (BMI) greater than 30 and with co-morbidities including diabetes, hypertension and cardiovascular disease.
However, unlike in the EPIC-HR trial, where those who had been vaccinated were excluded, for the present analysis, researchers included patients, regardless of their vaccination status.
The main outcome of the study was a composite of severe COVID-19 or COVID-19-related mortality. For their analysis, the researchers included demographic and co-morbidity data and which were adjusted for in the analysis.
Paxlovid and progression of COVID-19
A total of 4,737 individuals with a mean age of 68.5 years (42.1% male) were treated with paxlovid and compared with 175,614 individuals who tested positive but who did not receive the drug. In total, 77.8% of those given paxlovid had adequate COVID-19 vaccination compared to 75% of those in the non-paxlovid group.
Overall, the primary outcome occurred in 39 individuals receiving paxlovid compared to 903 in those not given the drug. Paxlovid was therefore associated with a significantly lower risk of severe COVID-19 or mortality (hazard ratio, HR = 0.54, 95% CI 0.39 – 0.75). Moreover, among the whole cohort, having adequate COVID-19 vaccination, was also associated with a significantly lower risk of the primary outcome (HR = 0.20, 95% CI 0.17 – 0.22).
When the analysis was restricted to those diagnosed with COVID-19 when omicron was the main circulating variant, paxlovid was also associated with a greater reduction in the primary endpoint (HR = 0.43, 95% CI 0.64 – 0.85).
Interestingly, among those given paxlovid and who were adequately vaccinated, there was still a significant reduction in the primary outcome (HR = 0.62, 95% CI 0.39 – 0.98) as well as among those not vaccinated (HR = 0.52, 95% CI 0.32 – 0.82).
The authors concluded that their study had demonstrated that in a real-world setting and during the period of time when omicron was the dominant variant, paxlovid was associated with a significant reduction in progression of COVID-19 and COVID-19-related mortality.
Citation
Najjar-Debbiny R et al. Effectiveness of Paxlovid in Reducing Severe COVID-19 and Mortality in High Risk Patients Clin Infect Dis 2022
30th June 2022
Stopping methotrexate (MTX) for two weeks after a third COVID-19 vaccination significantly enhanced the level of antibodies produced compared to continuing with the drug, according to the results of a randomised trial by a team of UK researchers.
The use of the immunomodulatory drug methotrexate, is known to adversely affect the humoral and cellular immune response to COVID-19 mRNA vaccines. In fact, studies have shown that seroconversion rates after COVID-19 vaccination are significantly lower in immunocompromised patients, especially organ transplant recipients.
As a result, it is important to implement strategies that can enable those who are immunocompromised to mount a satisfactory immune response.
In fact, the highest immune response occurred when MTX was discontinued two weeks after vaccination and this effect was confirmed in another study that specifically focused on stopping the drug two weeks after seasonal influenza vaccination.
Since the effectiveness of this approach has not been formally evaluated for the COVID-19 vaccine, for the present study, the UK undertook a randomised trial among immunocompromised patients prescribed methotrexate.
The Vaccine Response On/Off Methotrexate (VROOM) trial, randomised participants 1:1 to either suspension of MTX (suspend methotrexate) for two weeks immediately after their COVID-19 booster dose, or to continue with the drug as usual (continue methotrexate). Individuals were recruited from both rheumatology and dermatology clinics and who had been taking low dose MTX (< 25 mg/week) for at least 3 months. In addition, the researchers only enrolled participants who had previously received two COVID-19 vaccine doses.
The primary outcome of the study was the antibody response against the receptor-binding domain of the COVID-19 spike protein (S1-RBD) 4 weeks after receipt of the third COVID-19 vaccine dose. Secondary outcomes included S1-RBD antibody titres at 12 weeks post-vaccination and self-reported levels of disease activity.
Methotrexate suspension and S1-RBD antibody response
A total of 254 individuals with a mean age of 59.1 years (61% female) were included in the trial and randomised equally to either strategy. Overall, 51% of participants had rheumatoid arthritis, 34% psoriasis and 20% a skin condition alone. The median dose of methotrexate taken as 20 mg/week.
After 4 weeks, the geometric mean SI-RBD antibody titre was 22,750 U/ml in the suspend methotrexate group and 10,798 U/ml in the continue methotrexate group (p < 0.0001). This increase was independent of the dose and administration route of methotrexate, as well as type of immune-mediated inflammatory disease and age. Moreover, this difference in response remained significant at week 12 (16,520 vs 8094).
One downside of the study was that significantly more patients in the suspend methotrexate group self-reported at least one disease flare over the 12 week period compared to those who continued with the drug (71% vs 45%, odds ratio, OR = 2.83, 95% CI 1.64 – 4.88). However, these flares were generally self-managed and without any major impacts on quality of life.
The authors concluded that their strategy of stopping MTX was both safe and boosted the level of COVID-19 antibodies and called for further studies to examine the effect of stopping other immunosuppressant drugs on the level of antibody response.
Citation
Abhishek A et al. Effect of a 2-week interruption in methotrexate treatment versus continued treatment on COVID-19 booster vaccine immunity in adults with inflammatory conditions (VROOM study): a randomised, open label, superiority trial. Lancet Resp Med 2022
29th April 2022
Having a fourth COVID-19 vaccination at least four months after the third dose, offers better short-term protection against COVID-19-related adverse outcomes compared to only three doses of the vaccine. This was the main finding of a study by Israeli researchers from the Clalit Research Institute, Innovation Division, Tel-Aviv, Isreal.
Whilst millions of individuals have now received at least three doses of a COVID-19 vaccine, there is evidence that with the emergence of variants such as Omicron, vaccine effectiveness wanes over time. This was observed, for example, in one US study, during the Omicron period.
The authors found that vaccine effectiveness against emergency department visits was 87% during the first 2 months after a third dose but decreased to 66% among those vaccinated 4-5 months earlier. In fact, it is already apparent, albeit from a single study, that the rates of confirmed COVID-19 infection and severe illness were lower after a fourth dose of BNT162b2 vaccine compared to after only three doses.
Whilst this is an important finding, to date, the effectiveness of a fourth COVID-19 vaccination against other outcomes of interest such as hospitalisation and deaths remains uncertain.
For the present study the Israeli team examined the relative effectiveness of four compared to three doses of vaccine among those aged 60 years and older who had received a third dose at least 4 months earlier.
Using data contained within the Clalit Health Services, which is the largest payer-provide organisation in Israel, the team included patients deemed eligible for a fourth dose and who had no previously recorded infection with COVID-19.
There were a total of 5 outcomes of interest: COVID-19 infection; symptomatic COVID-19, COVID-19-related hospitalisation, severe COVID-19 and COVID-19-related death. All of these outcomes were assessed 7 to 30 days after the fourth COVID-19 vaccination and 14 to 30 days after vaccination. Those who received a fourth vaccine dose were matched with individuals who had only received three doses and with similar co-morbidities.
Fourth COVID-19 vaccination and adverse COVID-19-related outcomes
A total of 182,122 individuals who received a fourth vaccination dose and a median age of 72 years (53% female) were matched with a group of control patients (three vaccine doses).
During days 7 to 30, the estimated relative effectiveness of the fourth COVID-19 vaccination compared to three doses was 45% against a PCR confirmed COVID-19 infection, 55% against symptomatic COVID-19, 68% against COVID-19 hospitalisation and 74% against COVID-19-related mortality. Moreover, these effectiveness values were broadly similar when assessed 14 to 30 days after the fourth dose.
The authors discussed how use of a fourth dose appeared to be effective against the Omicron variant which was the main circulating variant at the time of the study (January 3 to February 18, 2022). They concluded that a fourth COVID-19 vaccination dose provided additional protection compared to only three doses in those older than 60 years of age.
Citation
Magen O et al. Fourth Dose of BNT162b2 mRNA Covid-19 Vaccine in a Nationwide Setting New Eng J Med 2022
18th March 2022
Seroconversion rates after a single COVID-19 vaccination among immunocompromised patients is low but improves after a second dose according to the findings of a systematic review and meta-analysis by researchers from the Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
Immunocompromised patients are at an increased risk severe COVID-19 illness and death. Moreover, it is recognised that among immunocompromised, solid organ transplant patients, a wide range of respiratory viruses cause significant morbidity and mortality among transplant recipients.
In a 2020 review of COVID-19 in cancer patients, it was noted how those with cancer are susceptible to severe clinically adverse events and a higher mortality from COVID-19 infection as well as morbidity and mortality from their underlying malignancy.
Although one 2018 systematic review found that seroconversion and sero-protection rates for influenza antigens were low in solid organ transplant recipients, no such reviews on the immunogenicity of COVID-19 vaccines and the overall seroconversion rates among cohorts of immunocompromised patients and been undertaken.
For the present study, the Singaporean team compared the seroconversion rates among groups of immunocompromised patients compared to immunocompetent controls. The team searched for studies that included patients with active cancer of solid organs, haematological cancers, organ transplant recipients, those with active immune mediated inflammatory disorders and for which a comparator group was included.
The primary outcomes of interest were seroconversion after the first and second COVID-19 vaccine doses.
Seroconversion rates after vaccination
A total of 82 studies were included in the meta-analysis.
Among those with haematological cancers, compared to immunocompetent individuals, the seroconversion rate after the first vaccination was less than half (risk ratio, RR = 0.40, 95% CI 0.32 – 0.50) and similar for those with solid cancers (RR = 0.55, 95% CI 0.46 – 0.65) and immune mediated inflammatory disorders (RR = 0.53, 95% CI 0.39 – 0.71). However, it was significantly lower for organ transplant patients (RR = 0.06, 95% CI 0.04 – 0.09).
After the second vaccination, the rates of seroconversion increased. For example, for haematological cancers (RR = 0.63) and among those with solid cancer (RR = 0.90) and whilst higher, remained very low, among organ transplant patients (RR = 0.39).
The authors did not include studies where a third COVID-19 dose had been administered in the meta-analysis because most studies did not include a comparator for control purposes. Nevertheless, based solely on a systematic review, they found that conversion rates for organ transplant patients improved by 36 and 66.7%.
The authors concluded that administration of a third vaccine dose (which has now become standard practice for everyone) is warranted for immunocompromised patients.
Citation
Lee ARYB et al. Efficacy of covid-19 vaccines in immunocompromised patients: systematic review and meta-analysis BMJ 2022
21st January 2022
A booster COVID-19 dose to cancer patients with solid tumours in receipt of active treatment, improves their immune response, according to the results of a study by a team from the University Paris Est Créteil, Paris, France.
Since the start of the COVID-19 pandemic, cancer patients have been deemed to be at high risk and thus a priority group for access to available vaccines. Nevertheless, as cancer patients were excluded from the vaccine efficacy trials, the nature and level of the immunogenic response to vaccination among cancer patients was uncertain.
Data from a study among cancer patients on treatment has shown that after a first dose, 29% of patients were seropositive and that this rate increased to 86% after the second dose. But there appears to be only one study in patients with cancer who have received a third dose of vaccine and which appeared to show greater immunogenicity.
For the present study, the French team wanted to evaluate the immunogenicity of two and three doses of a COVID-19 vaccine in cancer patients currently receiving chemotherapy and how this was affected by the type of oncology treatment and the timing of vaccination.
Using a prospective, observational design, the team included patients with solid organ active cancer, which they defined as ‘histologic confirmation of solid cancer under treatment within the previous 6 weeks or starting treatment during the next 2 weeks.’
The researchers collected information on the patient’s cancer diagnosis, therapy and cancer stages. All patients had received two doses of BNT162b2 on days 0 and 21 and those who had a prior history of COVID-19 infection or evidence of antibodies before vaccination were excluded.
A booster COVID-19 (i.e., third) dose was offered to all of those who had a weak humoral response one month after the second dose, which was defined by an anti-spike protein antibody level below 1000 units.
Findings
In total, 163 patients with a median age of 66 years (53% male) were included in the analysis. The most common form of treatment was chemotherapy (75%), followed by targeted therapy (16%) and immunotherapy (9%).
One month after the first vaccine, only 15% of patients had anti-spike antibody titres > 1000, although one month after the second dose, this proportion increased to 65%. A booster COVID-19 dose was offered to 36 patients whose antibody level remained below 1000 units, one month after the second dose. This resulted in 75% of these patients, achieving antibody levels > 1000, one month after their third dose.
In their analysis, age, sex, cancer type, lymphopenia and use of corticosteroids four or more weeks before vaccination, were not associated with the level of immune response at the time of the second dose or even 28 days after the second dose.
However, patients receiving either chemotherapy or targeted therapy had a lower anti-spike level than those given immunotherapy (odds ratio, OR = 5.4, 95% CI 1.5 – 20.2, p = 0.02). Other factors such as the time between vaccination and intravenous chemotherapy administration were also not associated with the intensity of the humoral response.
The authors concluded that a booster COVID-19 dose among those with solid tumours and in receipt of treatment, improved the immune response, highlighting the importance of a third dose in this patient cohort.
Citation
Fenioux C et al. SARS-CoV-2 Antibody Response to 2 or 3 Doses of the BNT162b2 Vaccine in Patients Treated With Anticancer Agents JAMA Oncol 2022.
13th January 2022
Vaccination has been found to result in a smaller reduction in the transmission of the Delta compared to the alpha variant according to a study by researchers from Oxford University, UK.
Vaccination against COVID-19 has been shown to reduce symptomatic infection and even onward transmission of the virus among household contacts. Furthermore, some data indicates that this reduced risk of onward transmission is because of a lower viral load among vaccinated individuals although other evidence points to a similar viral load among those who are vaccinated but infected with the Delta variant.
For the present study, the Oxford team used national contact testing data in England for adults (> 18 yeas of age) with both symptomatic and asymptomatic infections. Their analysis included vaccination with either BNT162b2 or ChAdOx1 to investigate differences in transmission from index patients infected with either variant. The analysis included regression models to determine any associations between onward transmission and the vaccination status of the index patient.
Findings
Among 146,243 tested contacts from a total of 108,498 index patients, with a median age of 34 years (51% female), 37% had a positive PCR test.
Using regression modelling, among index patients doubly vaccinated with BNT162b2 and who became infected, there was a significantly reduced risk of onward transmission of the Alpha variant (adjusted rate ratio, aRR = 0.32, 95% CI 0.21 – 0.48) compared unvaccinated individuals. Similarly, those with two vaccinations of ChAdOx1, also had a reduced risk of onward transmission (aRR = 0.48, 95% CI 0.30 – 0.78) compared to the unvaccinated.
In contrast, the extent of onward transmission of the Delta variant was reduced compared to Alpha by both vaccines but was greater among those doubly vaccinated with BNT162b2 (aRR = 0.50, 95% CI 0.39 – 0.65) compared to ChAdOx1 (aRR = 0.76, 95% 0.70 – 0.82). In other words, index patients vaccinated with BNT162b2 were less likely to have contacts with a positive PCR test for Delta compared to those given the ChAdOx1 vaccine.
The Delta variant was also associated with more onward transmission from both symptomatic index patients (aRR = 1.24, 95% CI 1.12 – 1.38) and from asymptomatic individuals (aRR = 1.40, 95% CI 1.22 – 1.59) and this was independent of both index and contact vaccination status.
Interestingly, the risk of infection with the Alpha variant among fully vaccinated contacts, was much lower among those given BNT162b2 (aRR = 0.15, 95% CI 0.11 – 021) compared to those fully vaccinated with ChAdOx1 (aRR = 0.40, 95% CI 0.27 – 0.59) and the magnitude of these reductions were similar for infections with the Delta variant.
Both symptomatic and asymptomatic index patients infected with the Delta variant had lower Ct values (i.e., higher viral loads) compared to those infected with the Alpha variant. When including Ct values in their regression models, the authors reported that lower Ct values were independently associated with increased transmission of either variant.
The authors concluded that vaccination was associated with a smaller reduction in transmission of the Delta compared to the Alpha variant.
Citation
Eyre DW wt al. Effect of Covid-19 Vaccination on Transmission of Alpha and Delta Variants. N Eng J Med 2022.
10th December 2021
The presence of subclinical axillary lymphadenopathy (sLAD) on mammography was significantly more likely among women who had received a COVID-19 vaccination, indicating that they should either delay screening or schedule visits before vaccination. This was the finding of a retrospective study by a team from the Baylor University Medical Center, Dallas, USA.
The term lymphadenopathy refers to lymph nodes that are abnormal in size and axillary lymphadenopathy, describes changes in the size and consistency of lymph nodes in the armpit. There are several potential causes of unilateral axillary lymphadenopathy including breast cancer and which therefore warrants further diagnostic investigations if these changes are observed during screening. Although the presence of sLAD has been observed in women who have received a COVID-19 vaccination, what remains uncertain, is the proportion of vaccinated women that will develop these lesions after either the Pfizer or Moderna vaccines.
Based on case reports of sLAD in vaccinated women, for the present study, the authors investigated the prevalence of the condition in all women who had attended a breast screening programme since December 2020 until April 2021. Data from medical records included the woman’s vaccination status, the vaccine received and the presence or absence of sLAD on mammography. The researchers cross-referenced prior imaging for all women to ensure that there was no baseline evidence of an axillary lymphadenopathy and excluded women who had presented for diagnostic mammography for a palpable axillary lump or pain and those with a history of breast cancer.
Findings
In total, 1027 women with a mean age range of 56.4 to 63.7 years were included in the analysis. There were 158 who received the Moderna vaccine, 144 (Pfizer) and 725 who had not been vaccinated. From these 1027 women, 43 (4.2%) had an sLAD; 3.3% of those who had been vaccinated compared to 0.9% who were unvaccinated and this difference was statistically significant (p < 0.01).
When comparing the two vaccines, the incidence of unilateral axillary lymphadenopathy was higher among those who received the Pfizer vaccination (13.2% vs 9.5%, Pfizer vs Moderna). Among the 43 women with sLAD and who were recalled after screening, vaccine induced sLAD was more likely to have resolved when re-scanned an average of 46.5 days since their COVID-19 vaccination.
The authors concluded that women who have received a COVID-19 vaccination within 8 weeks of their screening mammogram, were significantly more likely to present with a subclinical axillary lymphadenopathy and that this could result in unnecessary further diagnostic workload. They suggested that providers should either delay screening mammograms by 8 weeks in patients who have been vaccinated or that screening should be undertaken before vaccination to avoid unnecessary follow-up.
Citation
Raj S et al. COVID-19 vaccine-associated subclinical axillary lymphadenopathy on screening mammogram Acad Radiol 2021
8th December 2021
mRNA-1273 appears to be associated with a lower risk of COVID-19-related outcomes such as infection, hospitalisation and death compared to BNT162b. This was the finding of the first head-to-head vaccine effectiveness analysis undertaken by a group of researchers from the Brigham and Women’s Hospital, Harvard Medical School, Boston, US.
Randomised controlled trials have already demonstrated the effectiveness of the currently available COVID-19 vaccines. For instance, the mRNA-1273 vaccine (Moderna) has an efficacy of 94.1% at preventing COVID-19 illness and that a similar efficacy (95%) has been observed for BNT162b (Pfizer-BioNTech).
However, despite this near identical level of efficacy, other work has suggested that there might be differences between these two vaccines, even though they have the same mode of action. One study, for example, indicated that the mRNA-1273 vaccine produced a higher humoral immunogenicity than BNT162b, while other data show that the Moderna vaccine it is associated with a two-fold reduced risk of breakthrough infections compared to BNT162b and also results in a lower incidence of COVID-19-related hospitalisations.
For the present study, the US team turned to data from the national healthcare databases of the Department of Veterans Affairs, which is the largest US integrated healthcare system. The researchers sought to compare the relative effectiveness of the Moderna and Pfizer-BioNTech vaccines with respect to documented COVID-19 infections, symptomatic COVID-19, hospitalisation, admission to an intensive care unit (ICU) and death. In addition, the team examined the effectiveness of the two vaccines against the delta COVID-19 variant and examined these outcomes after 24 weeks.
Findings
During the period of study, there were 367,113 recipients of the BN162b and 397,690 of the mRNA-1273 vaccines. Over a 24-week period, 2016 COVID-19 infections were documented, of which 559 were detected as symptomatic, 411 which led to hospitalisation, 125 ICU admissions and 81 deaths.
The absolute risk of infection was low in both vaccine groups; 5.75 events per 1000 persons with the Pfizer-BioNTech and 4.52 with the Moderna vaccine. The 24 week risk ratio for infections for BNT162b compared to mRAN-1273 was 1.27 (95% CI 1.15 – 1.42), 1.39 for symptomatic infection, 1.70 for hospitalisation, 1.38 for ICU admission and 1.11 for death. Each of these risks was statistically significant apart from the risk of death. The overall risk difference expressed as events over 24 weeks per 1,000 persons was 1.23 for a documented infection.
Using these data, the authors calculated the number needed to vaccinate with mRNA-1273 instead of BN162b to prevent one case of documented infection was 813.
Analysis during the time period characterised by dominance of the delta COVID-19 variant, there was a 58% higher risk of infection in those vaccinated with BNT162b although this difference was non-significant (risk ratio = 1.58, 95% CI 0.85 – 2.33).
Commenting on these findings, the authors highlighted how their study had shown that recipients of the BNT162b vaccine had a 27% higher risk of a documented COVID-19 infection and a 70% increased risk of hospitalisation compared to the Moderna vaccine.
They concluded that the data provided evidence of a lower 24-week risk of COVID-19-related outcomes among those receiving the m-RNA-1273 vaccine compared to BNT162b.
Citation
Dickerman BA et al. Comparative Effectiveness of BNT162b2 and mRNA-1273 Vaccines in U.S. Veterans. New Eng J Med 2021
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