A group of researchers and doctors belonging to the OnCovid Study Group published a retrospective study of survival rate and other factors, in Europe, of vaccinated versus unvaccinated cancer patients. The article was published in the June 2, 2022 issue of Lancet Oncology. See article.
The objective was to compare the outcomes during the pre-vaccination period, the alpha and delta period, and the omicron outbreak.
The cancer patients were recruited from 34 institutions in the UK, Italy, and Spain.
The researchers utilized a number of indicators, including morbidity, defined as the number of symptoms (such as cough, difficulty breathing, loss of taste and smell, etc.) from COVID-19, hospitalizations due to COVID-19, use of supplemental oxygen, the number of therapies used to treat COVID-19, and COVID-19 mortality. The investigators divided the COVID-19 pandemic into three time periods (so far):
- Feb 27 – Nov 30, 2020 (pre-vaccination period)
- Dec 1, 2020 – Dec 14, 2021 (the combined alpha-delta wave)
- Dec 15, 2021 – Jan 31, 2022 (the beginning of the omicron wave)
3,473 cancer patients who were diagnosed with COVID-19 were included in the study. The investigators assessed the all-cause fatality rates at 14-days and 28-days post COVID-19 diagnosis.
Number of patients diagnosed by phase:
- 2033 (58.5%) patients were diagnosed during pre-vaccination period.
- 1075 (31.0%) were diagnosed during the alpha-delta wave.
- 365 (10.5%) were diagnosed during the omicron phase.
Besides fatality rate, the researchers also evaluated the rates of hospitalization, use of oxygen, use of specific therapies for COVID-19, and complications from COVID-19.
Patients diagnosed during the omicron phase tended to be younger than 65 years old and had fewer co-morbidities than those patients in the other two phases. On the other hand, more patients diagnosed in the omicron phase had advanced tumors and were receiving systemic treatment at the time of COVID-19 diagnosis.
Observation
Patients with cancer who were diagnosed with COVID-19 during the omicron phase had significantly lower mortality rates (both 14-day and 28-day) than those diagnosed in the other two phases. Likewise, they had lower hospitalization rates, fewer complications, and less need for oxygen. One could speculate that the improved outcomes were because the omicron variant does not attack tissues deep in the lungs as the other variants do. Secondly, the lower mortality rates could be due to the availability of therapies during omicron that were not available during the earlier phases. Or possibly, the biological differences in the omicron variant were a factor. The omicron variant does affect patients with hematological and thoracic cancers more than those having solid tumor.
The investigators found that none of the above were relevant to the improved prognosis of patients diagnosed during the omicron wave since unvaccinated patients diagnosed during omicron had similar 14-day and 28-day survival statistics as well as similar rates of hospitalization and complications from COVID-19 as those diagnosed during the alpha-delta phase. Instead, they “..found that the major determinant of the improved outcomes was previous COVID-19 vaccination”.
Conclusions
The following table shows the odds ratios and 95% confidence intervals for various outcomes comparing vaccinated and unvaccinated patients. Vaccinated patients received at least one dose of vaccine. The odds ratios and confidence intervals account for a standard error attributed to the participating centers. The following variables were accounted for in each model: country (UK vs. Spain vs. Italy), sex (male vs. female), age (³65 vs. <65), comorbidities (³vs. 0 or 1), tumor status at time of COVID (non-active vs. active disease), tumor stage at time of COVID (advanced vs non-advanced vs. unknown), and receipt of systemic anticancer therapy at time of COVID (yes vs. no vs. unknown).
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Odds Ratio Explained
The likelihood of a vaccinated person in the study of dying of any cause within 14 days of diagnosis of COVID-19 (OR = 0.16) is one-sixth of the likelihood of an unvaccinated person dying. For 28-days (OR = 0.26), it’s one in four. For hospitalizations (OR = 0.34), for every vaccinated person hospitalized there are three unvaccinated people hospitalized.
To note, there was no significant outcome difference between those who were vaccinated and those who were both vaccinated and boosted.
According to the investigators, the study demonstrated “..important confirmatory evidence that vaccination and booster doses are associated with a significant improvement in COVID-19-related outcomes in patients with cancer.” They go on to say that “…unvaccinated patients diagnosed in the omicron phase remain exposed to a risk of morbidity and mortality that is similar to the findings in previous phases of the pandemic, highlighting the importance of addressing vaccine hesitancy that might persist in some patients with cancer.”
We agree, get vaccinated, especially if you have co-morbidities and/or you are over 65 years old.
Long COVID and Number of Vaccine Doses
As noted on a July 9 podcast, This Week in Virology (TWiV): More than 2000 people die each week in the U.S. from Covid-19. The median incubation period from exposure is 6 days, varying from 2 to 14 days.
In a July 1, 2022 study of Long (or long-term) COVID published by the Journal of the American Medical Association (JAMA), 2560 healthcare workers who worked in nine Italian healthcare facilities were evaluated. Of the 2,560 people enrolled in the study, 739 (29%) contracted COVID-19.
Of the 739 patients who contracted COVID-19, 229 (31%) contracted Long COVID, defined as having at least one COVID symptom lasting more than 4 weeks. The number of vaccine doses was associated with lower long-term COVID: 42% in unvaccinated patients, 30% with one vaccine dose, 17.4% with two vaccine doses, and 16% with three vaccine doses (it’s unclear why the total added up to 105%, but the trend is clear). Also associated with long COVID were older age, high body-mass index, allergies, and obstructive lung disease.
See https://jamanetwork.com/journals/jama/fullarticle/2794072#.YsDSUeB6ZCg.twitter for the article.
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