A novel betacoronavirus, SARS-CoV-2, is spreading rapidly throughout the world. A large epidemic in South Africa may overwhelm available hospital capacity and healthcare resources which would be worsened by absenteeism of healthcare workers and other frontline staff (HCW). Strategies to prevent morbidity and mortality of HCW are desperately needed to safeguard continuous patient care. Bacillus Calmette-Guérin (BCG) is a vaccine against tuberculosis (TB), with protective non-specific effects against other respiratory tract infections in in vitro and in vivo studies, with reported morbidity and mortality reductions as high as 70%. We hypothesize that a BCG vaccination may reduce the morbidity and mortality of healthcare workers during the COVID-19 outbreak in South Africa.
Morbidity and mortality attributable to COVID-19 is devastating global health systems and
economies. Bacillus Calmette Guérin (BCG) vaccination has been in use for many decades to
prevent severe forms of tuberculosis in children. Studies have also shown a combination of
improved long-term innate or trained immunity (through epigenetic reprogramming of myeloid
cells) and adaptive responses after BCG vaccination, which leads to non-specific protective
effects in adults. Observational studies have shown that countries with routine BCG
vaccination programs have significantly less reported cases and deaths of COVID-19, but such
studies are prone to significant bias and need confirmation. To date, in the absence of
direct evidence, WHO does not recommend BCG for the prevention of COVID-19.
This project aims to investigate in a timely manner whether and why BCG-revaccination can
reduce infection rate and/or disease severity in health care workers during the SARS-CoV-2
outbreak in South Africa. These objectives will be achieved with a blinded, randomised
controlled trial of BCG revaccination versus placebo in exposed front-line staff in hospitals
in Cape Town. Observations will include the rate of infection with COVID-19 as well as the
occurrence of mild, moderate or severe ambulatory respiratory tract infections,
hospitalisation, need for oxygen, mechanical ventilation or death. HIV-positive individuals
will be excluded. Safety of the vaccines will be monitored. A secondary endpoint is the
occurrence of latent or active tuberculosis. Initial sample size and follow-up duration is at
least 500 workers and 52 weeks. Statistical analysis will be model-based and ongoing in real
time with frequent interim analyses and optional increases of both sample size or observation
time, based on the unforeseeable trajectory of the South African COVID-19 epidemic, available
funds and recommendations of an independent data and safety monitoring board.
Given the immediate threat of the SARS-CoV-2 epidemic the trial has been designed as a
pragmatic study with highly feasible endpoints that can be continuously measured. This allows
for the most rapid identification of a beneficial outcome that would lead to immediate
dissemination of the results, vaccination of the control group and outreach to the health
authorities to consider BCG vaccination for all qualifying health care workers.
Biological: Bacille Calmette-Guérin (BCG)
BCG vaccine will be given intradermally in the upper arm after randomization.
Other Name: BCG-Vaccin SSI [Statens Serum Institut], Danish strain 1331
Other: Placebo Comparator
Placebo injection will be given intradermally in the upper arm after randomization.
Other Name: 0.9% Sodium Chloride
Inclusion Criteria:
- Men and women aged ≥18 years
- HCW or other frontline staff currently in contact with, or anticipated to be in
contact with, patients with SARS-CoV-2 infection.
- Ability and willingness to provide informed consent.
- Can be reached by mobile phone for follow-up
Exclusion Criteria:
- Known allergy to (components of) the BCG vaccine or serious reaction to prior BCG
administration.
- Known active tuberculosis or any other active or uncontrolled condition that, in the
opinion of the investigator or designee, makes participation unsafe or makes it
difficult to collect follow-up data over the study period.
- HIV-1 infection
- NOTE: If evidence of recent HIV negative test is not available, rapid point-of-care
testing will be undertaken as part of screening with a separate informed consent
process.
- Symptoms of respiratory tract infection which, in the opinion of the investigator or
designee, is likely to interfere with the objectives of the study.
- Known medical history of any of the following immunocompromised states:
- Neutropenia (less than 500 neutrophils/mm3)
- Lymphopenia (less than 400 lymphocytes/mm3)
- Solid organ or bone marrow transplantation
- Primary immunodeficiency
- Active solid or non-solid malignancy or lymphoma within the prior two years
- Pregnancy and breastfeeding
- Current treatment with the following medications:
- Chemotherapy
- Anti-cytokine therapies
- Current treatment with oral or intravenous steroids defined as daily doses of
10mg prednisone or equivalent for longer than 3 months
- Any experimental, unproven treatment against SARS-CoV-2 infection or COVID-19
including but not limited to chloroquine, hydroxychloroquine, remdesivir,
lopinavir/ritonavir and interferon beta-1a.
TASK Foundation
Cape Town, Western Cape, South Africa