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The Race for a COVID-19 Vaccine: A Sprint or a Marathon?
Posted August 4, 2020
The race to develop a safe and effective vaccine against severe acute respiratory syndrome coronavirus, commonly known as COVID-19, is one of the most important public health issues facing the world today. To achieve herd immunity and thereby reduce the risk of COVID-19, it is estimated that immunity rates of 60 percent or more are needed, and achieving these rates of immunity without an effective vaccine would impute deaths of millions of people after infection through normal transmission paths.
An article in Nature illustrates and reviews the vaccine basics. Four basic types of vaccines have been proposed—intact virus, viral vectors, nucleic acid (DNA/RNA) and protein-based. Intact viral vaccines, such as those that protect against measles and polio, are made from inactivated or weakened viral strains. Viral vector vaccines, including the Ebola vaccine, are derived from genetically engineered weakened viruses that produce coronavirus proteins to raise an immune response. DNA/RNA vaccines use nucleic acid insertion into human cells that encode viral proteins that provoke host immune response. They are easy to engineer and develop but are unproven, and no licensed vaccines are made this way. Protein-based vaccines work by infusing various viral proteins (mostly against the spike protein) to elicit an immune response.
The first stage of validating proposed vaccines is in small studies of healthy and usually young volunteers. A Phase 1 trial of SAR-Co-V2 vaccines and commentary have been published in the New England Journal of Medicine.
Phase 1 trials are done to determine the effectiveness of escalating as measured by antibody response and to determine incidence of side effects in a small number of recipients. Publicly announced vaccine candidates that are being developed at “warp speed” are covered in JAMA.
Phase 2 trials are larger, often include very young and very old patients and are intended as much larger trials of safety and antibody response. Large trials are needed to investigate the true effectiveness in reducing infection with SARS-CoV-2 in a large population exposed to the larger populations with endemic or epidemic rates of infection. These trials are now being announced in the press and are “of the minute”; that is, starting or near starting to accrue volunteers.
Paradoxically, it is easiest to validate effectiveness of a vaccine with a growing or high level of prevalence of the infection, so the high rates of infection currently found in southern and western states may enable quicker validation of vaccine utility. Of note, many tentative or proposed therapeutic drug trials planned in China during the early stages of the pandemic had to be halted as the disease incidence dropped dramatically, as quarantine and other measures slowed and stopped SARS-CoV-2 infection by late spring. Concern for the speed with which a vaccine could be developed has thus led to discussion of challenge trials of vaccines—administering a vaccine to healthy volunteers and then challenging them with an infectious dose of SARS-CoV-2 virus to see if the vaccine truly confers immunity. This approach is controversial ethically, and has strong proponents and opponents.
Vaccine development against COVID-19 disease is moving at the most rapid pace in the history of vaccine development. Historically, vaccine development has been a three- to six-year process, but discussion of an effective vaccine for COVID-19 within 2020 is widespread. Caution is needed here: witness the nearly 40-year history of attempted vaccine development for AIDS, which has yet to be successful.
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From Alaska to Appalachia: Rural Surgeons Tackle Unique Challenges Fighting COVID-19
Posted August 4, 2020
Nine surgeons from rural and remote communities in the U.S. share early experiences preparing for the COVID-19 pandemic. Relating experiences remarkably different from those of health care professionals in urban areas in the U.S. most affected by the first stages of the outbreak, they describe the challenges of organizing resources in facilities already struggling with poverty-stricken communities far from established health care resources and supplies. From Alaska to Appalachia and the Navajo Nation to the rural Midwest, they show the leadership and professionalism that exemplify rural surgery.
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Controversy Continues Over Use of HCQ as a Prophylaxis for COVID-19
Posted August 4, 2020
The use of hydroxychloroquine (without azithromycin) for prophylaxis against the development of COVID-19 was tested in 821 U.S. and Canadian patients who were exposed to the virus—88 percent of which were high risk exposures—in a randomized, double-blind, placebo-controlled trial. The patients were recruited through standard media and social media. The investigators found no statistical benefit to the use of HCQ in preventing new illness compatible with COVID-19. In patients receiving prophylactic HCQ, 11.8 percent developed such an illness, and in the patients receiving placebo, 14.3 percent developed illness consistent with COVID-19. The difference between the two groups was -2.4 percent in favor of HCQ use , but the 95 percent confidence interval was -7.0 to 2.2, so statistical difference was unconfirmed. Incidence of side effects (largely gastrointestinal) was much higher in the HCQ group and no arrhythmias or deaths were recorded. Only two patients were hospitalized.
This study does have its shortcomings. It was performed in March, and only a small minority of the cases or illnesses attributed to COVID 19 were confirmed by polymerise chain reaction testing because of limited testing availability, so absolute confirmation of disease was not the standard for the diagnosis of COVID 19. The study will require repeating by another institution or group to confirm these results.
The use of HCQ remains controversial. The definitive/authoritative study to determine utility/effectiveness of the use of HCQ in prophylaxis or treatment of COVID 19 has yet to be published.