South Africa is currently affected by the global pandemic of COVID-19, a predominantly respiratory disease caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). COVID-19 appears to cause more severe disease and deaths in elderly persons and those living with underlying chronic illnesses.(1) We aim to address whether or not pneumococcal conjugate vaccine has a role in reducing morbidity and mortality in the South African context.
The reported morbidity and mortality from COVID-19 is predominantly due to development of a primary viral pneumonia in persons unable to suppress the replication of the virus.(2) This usually occurs 7 to 10 days into the illness, often resulting in Acute Respiratory Distress Syndrome. Persons most at risk of developing severe COVID-19 are those with underlying diabetes, chronic lung disease, coronary artery disease, any form of immune suppression or those >65 years of age.(3)(1)(4)(5)
Unlike influenza, there is little evidence to support secondary bacterial infection as a major cause of morbidity or mortality following SARS or Middle Eastern Respiratory Syndrome (MERS) disease (two corona viruses closely related to SARS-CoV-2).(6) However, as time progresses there may be more case reports of pneumococcal pneumonia following COVID-19 disease in the China and Europe. Recommendations in China for COVID-19 patients who were deteriorating were to give broad-spectrum antibiotics early to prevent secondary infection.(7) To date, no evidence has been forthcoming of SARS-CoV-2 and pneumococcal co-infection.
Streptococcus pneumonia is a common cause of bacterial pneumonia and bacteraemia amongst all populations, especially amongst HIV-infected persons, those with chronic conditions and the elderly.(8)(9) In South Africa in 2018, 70% of patients with invasive pneumococcal disease (IPD) were HIV-coinfected, and in addition, 45% of IPD patients had a chronic condition known to put them at high risk of pneumococcal disease.(10) In-hospital mortality from IPD was 26%, increasing with increased age. Serotypes 8, 3, 19A, 12F, 4 and 19F are the top 6 serotypes causing pneumococcal disease in persons >5 years, and four (3, 19A, 4 and 19F) of these six serotypes are included in the 13-valent pneumococcal conjugate vaccine (PCV13).(10)
Pneumococcal conjugate vaccine (PCV) is a vaccine that targets specific serotypes of the bacteria, Streptococcus pneumonia. There is no protection offered against viral pathogens such as, SARS-CoV-2 or influenza. PCV13 is currently offered in the South African Extended Programme of Immunisation (EPI) to infants at 6 weeks, 14 weeks and 9 months. PCV13 is licenced for use in young children and adults >18 years.(11)
In 2017, the South African guidelines for management of community acquired pneumonia recommended PCV13 use in all adults > 50 years.(12) In turn, adults >65 years who are pneumococcal vaccine naïve should receive PCV13 followed by pneumococcal polysaccharide vaccine (PPV23) one year later. In addition, younger adults (>18 years) with underlying chronic conditions or immunocompromising conditions (including HIV) should receive PCV13 followed 2 months later by PPV23.
Despite the unknown interaction of pneumococcal disease and COVID-19, SARS-CoV-2 has emerged in South Africa at the beginning of autumn and will most likely be circulating widely in our country through the winter/spring season and beyond. In South Africa, we are still awaiting the onset of the annual Southern Hemisphere influenza season which usually begins in late April to May, and in addition the Respiratory Syncytial Virus (RSV) seasonal peak has not yet occurred. Therefore, any intervention to lower the risk of becoming infected with any respiratory disease at this time may be of benefit. Secondary bacterial infections with pneumococcus commonly follow influenza disease and use of influenza vaccine and PCV13 may reduce this burden in the elderly and those with underlying illnesses.(13)
Lowering the risk of acquiring a respiratory infection, will allow for less visits to clinics and less hospital admissions, thus decreasing the burden on the health infrastructure at this time and lowering ones’ exposure to acquiring COVID-19 in the hospitals/clinics.
Although PCV13 does not protect against COVID-19 mild or severe disease or COVID-19 pneumonia, it is targeted at a substantial portion of currently circulating adult pneumococcal serotypes, and thus could play a role in prevention of a portion of secondary pneumococcal pneumonia infections in those with underlying conditions and the elderly.(14)
There is no benefit of giving PCV13 to prevent hospitalisations due to COVID-19, however it may prevent secondary bacterial infections due to any of the viruses circulating this winter season. In line with WHO recommendations, PCV13 should be considered in those at high risk of developing pneumococcal disease or severe COVID-19, to prevent bacterial pneumonia, hospital admissions and comorbidities associated with severe disease.(15) PCV13 can be given concomitantly with the influenza vaccine. In high risk persons who are <65 years, consider giving PCV13 followed by PPV23 after 2 months to extend the range of serotype cover.