BY SAARANI VENGADESEN
THE Delta variant of Covid-19 virus is redefining the term “herd immunity” and further mutation that renders vaccines ineffective will be a huge disaster. One way to stop this is through vaccination to give less time for the virus to mutate.
Datuk Dr Christopher Lee, the former National Advisor for Infectious Disease at the Ministry of Health Malaysia (MOH) said this, in a recent a webinar session organised by The Petri Dish and Science Media Centre.
“The Delta variant is a game changer and it will redefine the concept of herd immunity,” Lee told the webinar, which was supported by Duopharma Biotech as the company’s Corporate Social Responsibility (CSR) project.
The infectious disease specialist also addressed issues related to post-vaccination such as immunity period, the emergence of new variants, antibody self-test kits, and children’s immunisation programme during the fourth episode of the “YakiniVaksin” webinar themed “Merdeka daripada Covid-19”.
Lee explained that generally Covid-19 patients are divided into five categories. The first two categories are mild infections with slight symptoms such as fever or flu.
“The third stage presents moderate infections which still needs hospitalisation but the fourth and fifth stages are categorised as high risk as the patient’s lungs are severely infected .
“The category of Covid-19 patients is determined according to their severity level on the day they are confirmed as Covid-19 positive,” he added.
According to the daily data released by MOH, most of the cases now fall between category 1 to 3 since the country’s immunisation programme is up and running.
He attributed this to the intensity of mass screening where Covid-19 patients are now being identified at an early stage of infection before severity sets in. He also pointed out that completely vaccinated patients show only a milder version of Covid-19. Most of these patients mostly present flu, cough and fever symptoms.
He urged the public to get tested early if they show these Covid-19-like symptoms.
“Has the demand for ventilator use in intensive care units reduced with 40% of the population vaccinated currently?” This question was put forward by session moderator Dr Mahaletchumy Arujanan, editor-in-chief of The Petri Dish and co-founder of Science Media Centre Malaysia.
Lee replied, citing the experience of Klang Valley hospitals where the situation was very critical two months ago, with heavy caseloads stressing the healthcare system and frontline staff. However, the situation has profoundly eased in tandem with the vaccination programme.
“Similar to our country, the United Kingdom also has high numbers of daily reported cases but their hospitalisation and death rates have decreased. This proves that vaccines have reduced the severity of infections.
“Most of the cases being reported now are just mild infections that can be managed effectively and most of the patients being hospitalised today are those who are not vaccinated,” added Lee.
The Delta variant as a game-changer
Lee noted that the Delta variant has changed the entire ballgame in this pandemic globally.
“According to the President of the United States, they would have exited the pandemic a long time ago if the Delta variant did not spring up,” said Lee.
He said virus mutation is like a race and they mutate faster when more opportunities are given to them such as social gatherings and poor adherence to the Standard Operating Procedures (SOPs).
“The Delta variant has reduced the efficacy of vaccines slightly but all vaccines are still effective against the infection. It is our responsibility not to give opportunities for the virus to mutate further because there are possibilities for more virulent variants to emerge. This could render the vaccines to become less effective.
“If the vaccine becomes ineffective we will be in a dire situation again,” stressed Lee.
To another question by a webinar participant on the difference between Delta and Delta Plus variant, Lee explained that mutation occurs when there is a structural change on the spike protein of the coronavirus.
“The Delta Plus variant emerged when further mutation occurred on the original Delta variant. However, the intensity of the mutation was severe enough to make it a new and separate variant.
“We don’t want Delta Plus to become a new variant,” said Lee. He also mentioned the Lambda variant that originated from Peru which is said to be more virulent than Delta but fortunately, it has not spread to other parts of the world.
Are children ready for the jab?
Mahaletchumy asked another question on safety data of the vaccines for children and Lee explained that safety data for children aged 13 to 17 years old shows that they are as safe as for adults.
He said research is still ongoing to determine vaccination for children under 12 years old. Lee urged parents to bring their children for vaccination once it is commenced – as at the start of the pandemic, death toll among children was very low but this is changing now and it could also be due to the Delta variant.
To another question from a participant – whether children will form the majority of cases once adults are vaccinated, Dr Lee said the herd immunity will protect unvaccinated children.
“It is important for parents, teachers, restaurant workers and others to be vaccinated,” explained Lee.
To another question Dr Lee said: “There is a possibility for a vaccinated individual to be infected with Covid-19 but the transmission rate to another individual decreases by 50% after a few days, compared to an unvaccinated individual”.
The immunity period post-vaccination
Studies show that current vaccination gives protection from eight months to a year but the data is not clear on this yet. Lee emphasised that no vaccine gives 100% protection for any disease.
On another question about booster shots, Lee said in the current situation mass vaccination has to be prioritised before going for booster shots as there is still a shortage of vaccines globally.
He said the United States has begun with its third booster dose and priority is given for immunocompromised individuals who are more vulnerable to infections.
“For Malaysia, we can move to third dose once everyone is vaccinated and when we have secured enough vaccine supply,” added Lee.
Movement control relaxation: A good move?
Lifting movement restrictions for fully vaccinated adults is a move to support the economy. Lee urged employers to ensure their workers are vaccinated to create a safe bubble for everyone. He also highlighted the importance of ensuring air ventilation in a closed environment.
“Indoor ventilation has to be emphasised as it can improve the quality of the air we breathe and reduce the risk of Covid-19 spreading indoors.
Antibody self-test kits
Asked if serology test-kits that determine the presence of antibodies are accurate, Lee said there are many types of antibodies and not all can be detected by these test-kits.
“Many are focussed on neutralising antibodies but what is important are also the T-cells and memory cells.”
Lee also cited the Food & Drug Administration (FDA), which currently does not recommend serology tests because it is still uncertain what is the amount of antibody required to protect against Covid-19, and also because every individual responds to vaccination differently.
He said the Polymerase Chain Reaction (PCR) is the gold standard for Covid-19 diagnosing but every test has its pros and cons. PCR could give a false negative if the swab was not done properly or the person moves during the swab.
“Saliva test kit is good but it might show a false negative too as no test is 100% accurate. If symptoms still persist, an individual has to be tested again.”
“In my opinion, the saliva test kit is a good option, whereby individuals can test themselves at an early stage of infection. They can also decide how often they want to be tested since it is relatively cheap and quarantine themselves immediately if they are tested positive,” explained Lee.
Pandemic to Endemic
When asked by the moderator, if the pandemic will become endemic, Lee cited the H1N1 pandemic of 2009 which is also an infectious disease similar to Covid-19. However, today it is at an endemic stage which does not cause many complications, but it is not completely gone.
“There is no other way to get out of a pandemic except, except through large scale vaccination programmes and SOPs until an antiviral drug is discovered,” Lee said.
