COVID-19, Pandemics & Vaccinations

More than a year has passed since the first cluster of COVID-19 infection was reported in a province in China. That first cluster occurred just around the time of a festive season that traditionally had many people going home to spend time with their loved ones or travel overseas for holidays. This contributed to more clusters occurring elsewhere around the world, leading to what has now become a global pandemic.

The word pandemic has Greek origins from the word pandemos meaning all (pan) people (demos). Thus, further adding to the understanding of a pandemic, which the World Health Organisation (WHO) defines as the worldwide spread of a new disease. This disease refers to an infectious disease from a micro-organism, like bacteria or viruses that causes a person to fall ill and can spread from person to person. The spread from person to person leads to clusters of infected persons, especially when it occurs rapidly. Many clusters of infection within a geographical area or in a population is known as an epidemic.

Epidemics and pandemics have occurred at various times in the history of mankind. The Black Death Plague of the 14th century and The Great Plague in the 17th and 18th centuries are some of those that have been often described because of the sheer number of deaths caused. In the 20th century, there was the Spanish flu that claimed at least 40 million lives between 1918 and 1919, and the Smallpox pandemic in 1520 with 56 million lives lost. A bacterial infection caused the plague, whereas the pandemics that occurred later were mainly due to viruses.

Smallpox has earned its name in medical history not only for the pandemic it caused, but it is also known as the first infectious disease to be successfully eradicated. The last known case of smallpox was documented in 1978. This eradication stemmed from a global effort that WHO spearheaded. The World Health Assembly endorsed the successful eradication of smallpox in 1980.

Smallpox presents with a fever followed by a rash that develops into sores. It had a high mortality rate of 30 percent and those who survive bear scars from the sores. During the time of smallpox infections, another virus caused a similar but milder illness – cowpox. It is an infection that is transmitted from cows infected with the virus. It was observed that those who had cowpox previously were protected from smallpox. This led Dr Edward Jenner to experiment with material from cowpox on healthy individuals and found that this protected the individual from smallpox when exposed to it. This was among the earlier forms of vaccination.

Today, there are effective vaccines against mumps, measles, rubella, influenza, poliomyelitis and other infections. Vaccination programmes in early childhood have been shown to reduce mortality and morbidity. Similarly, vaccination programmes for the elderly have shown that influenza vaccination reduces hospitalisation and complications in those who are vaccinated.

The history of pandemics has provided many lessons in various domains from healthcare delivery, preventive medicine to public health and more. There is also the impact on people’s lives and the economy. Knowledge of infectious diseases, its treatment, and vaccination programmes provide an ever-increasing knowledge base to help overcome future epidemics and pandemics.

It is this knowledge that has expedited our progress in dealing with the present pandemic. The virus that causes the COVID-19 pandemic belongs to the family of Coronaviruses, so named because of its crown shape. The virus has been named SARS-CoV-2 and the infection it causes, COVID-19. The extent and severity of the infection have been well reported. Sadly, many lives have been lost as a result of being infected with the virus.

The virus spreads through droplets which means that when an infected person sneezes or coughs, small droplets of fluid are generated and expelled from the person. These small droplets of fluid come from the person’s secretions that are produced in greater amounts from the infection. They contain the virus which may then infect others. Wearing masks protects the user from exposure to such droplets. The masks also prevent the spread of the virus if the person is infected. In addition, putting a distance of at least one metre between persons reduces the risk of such droplets reaching another person. This is the rationale for safe distancing.

When infected, the person does not immediately fall ill. Instead, the person undergoes a phase where the virus infects more cells in the body and produces more virus from those infected cells. This phase is the incubation phase, and the infected person may continue to spread the virus to other healthy individuals. Even at this stage, the person is infectious to others, hence it has been termed the ‘pre-symptomatic phase’.

The next phase is when the patient starts to become unwell and fever develops, along with acute respiratory symptoms which vary from person to person. These respiratory symptoms include dry throat, cough, runny nose, congestion of nose, breathlessness and loss of taste or smell.

Some develop nausea, vomiting or diarrhoea. There may be fatigue, muscle aches and pains. The symptoms may range from mild to severe.

Patients with severe symptoms may deteriorate and require intensive care. Those with chronic illnesses are at risk of developing severe symptoms. They may also develop more complications as a result of their chronic illnesses. The elderly is more vulnerable to such infections. They may acquire it easily and develop more complications. Outbreaks of COVID-19 in nursing homes in some countries have caused more deaths as the residents there are old and have chronic illnesses.

It has become noticeably clear that prevention of the spread is necessary in the strategy to contain the virus. Some countries have imposed lockdowns to curb its spread. These were intended to reduce interaction among people that would otherwise have allowed the virus to spread. Measures like quarantine for incoming travellers allows for their isolation until they have passed the incubation period. The period of quarantine is about 14 days. Those who have acquired the infection prior to arrival will not spread the infection as they would be in quarantine. The inclusion of tests during the quarantine allows for earlier detection of those who are infected before they fall ill. They can then be provided with prompt medical care, rather than allowing symptoms to appear.

Medical care for COVID-19 infection is largely supportive in nature. Unlike bacterial infections that can be treated with antibiotics, treatment of most viral infections is supportive and medications are given to control symptoms like fever. There are antiviral drugs available which work to disrupt the way the virus spreads within the human body. In an infected person, the virus attaches itself to the cells and stimulates it to produce more copies of the virus which are then released to attack other normal cells.

Antiviral drugs trick the virus to attach to it instead of the cells in our body, thus preventing the infection from taking hold of cells. Some may stop the virus from making copies of itself after it has entered the cell. Others prevent the release of the virus from infected cells. Although antiviral drugs are used for COVID-19 infections, they have not been shown to be highly effective.

The focus has therefore shifted to preventing the infection. This may be achieved through vaccination. Vaccination is a process that involves giving a person a vaccine to prevent the person from acquiring an infection. The person’s immune system becomes activated with the vaccine and produces antibodies which protects against the infection. This process of developing immunity is called immunisation. Technology and medical science have brought about newer and safer vaccines which are synthetically produced. These are safer than using dead viruses or material from them.

In Singapore, there are two vaccines that have been approved for use against COVID-19. They are the Pfizer-BioNTech and the Moderna vaccines. These vaccines use a newer method, which involves messenger RNA (mRNA), for immunisation. mRNA are genetic material that are used to code for proteins. They are not incorporated into the cells’ DNA but instead, are eventually broken down. Cells normally generate mRNA to produce a variety of proteins for the function of cells. In the case of mRNA vaccines for COVID-19, they produce proteins that are found on the SARS-CoV-2 virus which in turn stimulates and teaches the immune system how to fight it. Therefore, if the person does become infected, the body immune system can mount a response to fight it.

Vaccination improves a person’s immunity to COVID-19. It prevents the person from getting the infection and spreading it to others. Some people develop a partial response to vaccination and may not be fully immunised, which means that they may get a milder infection with fewer complications. It is therefore important to recognise that vaccination helps most people. Based on the current available evidence, the two vaccines in Singapore have an effectiveness rate of more than 94 percent.

Vaccines are considered medications. Some side effects may occur with vaccines, which are not peculiar to the COVID-19 vaccine alone. Common side effects include pain or swelling at the injection site, fever or chills. These may be relieved with medications like paracetamol. There is a small risk of a severe allergic reaction called anaphylaxis where a person may develop difficulty breathing and swelling of eyes and lips. This is a serious reaction that requires immediate attention. Fortunately, this is rare.

There have been concerns about the speed of development and implementation of COVID-19 vaccines, especially its safety and effectiveness. There is a mandatory process to develop a vaccine which is regulated by independent agencies. In the past, the process may have been limited by bureaucratic red tape and processes; however, these have been expedited to reduce delays. There are also trials conducted to ensure that the vaccines are safe for use. The abundance of caution that is seen in the vaccination programmes for COVID-19 indicates a mindful awareness that safety remains paramount.

The vaccination programme in Singapore has been conducted in a stepwise manner. Frontline workers, especially those in healthcare, were offered vaccinations first. Healthcare workers have willingly stepped forward to be vaccinated, to reduce their risk of getting infected and to protect their families. Subsequently, those who are vulnerable were offered vaccinations. These would be the elderly, aged 70 and older. Given Singapore’s ageing population, it is imperative that we advocate immunisation to protect the elderly. The programme has since been expanded progressively to those in education, transport as well as delivery and now, to those who are younger.

With more people immunised through vaccination, it is anticipated that the return to normalcy will occur sooner rather than later. Nonetheless, it remains that safe management measures should continue. As we move towards normalcy, some new norms will continue – being responsible for our health by seeing a doctor when unwell, wearing a face mask, and washing one’s hands frequently. It is only with everyone’s cooperation that we will be able to overcome this pandemic. ⬛


Dr Norhisham Main is the Head of Division for Supporive Care and Palliative Medicine, and a Senior Consultant in Geriatic Medicine and Palliative Medicine at the Ng Teng Fong General Hospital.

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