MORE than two billion people have received at least one dose of a Covid-19 vaccine since public vaccination programmes started worldwide.
This number includes more than two million Malaysians.
This is an astounding achievement in only a few months, with science, manufacturing and healthcare delivery systems exceeding expectations in this historic and global mission.
Emerging evidence shows that these vaccinations have significantly reduced case numbers, hospitalisations and deaths in countries like Germany, France, Israel and the United Kingdom.
But challenges remain, notably in vaccine equity (most of the two billion doses are in rich countries), emerging variants (which may reduce the effectiveness of existing vaccines) and vaccine confidence (which depend on how the public understands vaccinations and statistics).
Over time, the government will need to be more transparent and deploy effective strategies to maintain and increase vaccine confidence.
Today, we take a look at the communications surrounding breakthrough infections and vaccine side effects.
The US Centers for Disease Control and Prevention (CDC) defines “vaccine breakthrough infection” as detection of a SARS-CoV-2 infection 14 or more days after completing all recommended doses of a vaccine authorised by the US Food and Drug Administration (FDA).
In other words, a breakthrough infection happens when someone contracts the SARS-CoV-2 virus despite being fully vaccinated.
All levels of infection severity are counted, from those with zero symptoms to those who eventually die from Covid-19.
At the time of writing, there is a 0.01% rate of breakthrough infections among fully vaccinated populations in the United States. Breakthrough infections occur for several reasons.
One, all approved Covid-19 vaccines are highly effective, but are not 100% perfect.
Two, all approved Covid-19 vaccines are excellent at reducing the risk of death, severe disease or hospitalisations, but they do not yet achieve the ideal of full protection against any form of infections (known as “sterilising immunity”).Three, breakthrough infections will continue to happen until we reach population herd immunity, which will significantly reduce the risk of transmitting the SARS-CoV-2 virus.
Four, emerging virus variants may reduce the effectiveness of vaccines, leading to breakthrough infections.
And five, different people have different levels of immune system responses to different vaccines, with some having a lower immune response that does not adequately protect them.
More surveillance needed
The good news is that 0.01% is a very low rate of one breakthrough infection for every 10,000 vaccinated people.
This means that among the two million Malaysians already vaccinated, we should expect a total of about 200 breakthrough infections over three to six months.
These 200 infections are unfortunate of course, but is far better than the thousands of daily infections in those who are not yet vaccinated.
Breakthrough infections do not mean that the Covid-19 vaccines have failed, as they were designed to protect from severe disease, not deliver sterilising immunity.
All approved Covid-19 vaccines confer significant benefits and should definitely be taken by everyone.
However, the presence of breakthrough infections after vaccinations indicate that the government should consider three additional policies.
Firstly, the Health Ministry (MOH) should consider performing more virus surveillance among vaccinated Malaysians.
Currently, the US CDC believes that passive surveillance for breakthrough infections is possibly under-reporting cases because many infections are asymptomatic.
Active surveillance will provide useful data points to assess the real-world effectiveness of Malaysia’s vaccination programme, potentially via the MySejahtera app.
The level of activeness of the surveillance depends on several variables and can be determined by the MOH and the Covid-19 Immunisation Task Force (CITF).
Secondly, there should be increased genomic testing among breakthrough infection cases.
Genomic testing or surveillance is a way to see if the viral strain among patients with breakthrough infections is the original SARS-CoV-2 strain or emerging viral variants of concern (VOCs) like the Alpha, Beta, Delta and Gamma variants (these are the new names for emerging VOCs announced by the World Health Organisation on May 31).
This could also provide data to help improve the design of second generation Covid-19 vaccines.
Thirdly, the MOH should consider evaluating protective immune responses through antibody and T-cell tests for vaccinated high-risk populations like immunocompromised patients.
This will enable doctors and public health professionals to know if these high-risk populations have developed adequate immune response after vaccination.
Those without adequate immune response may benefit from booster doses.
Side effects increased
A separate, but linked issue on vaccine confidence is the side effects.
The good news is that we are now familiar with common side effects like injection site pain, body aches and slight fevers, as more and more of our family and friends receive vaccinations.
The bad news is that serious side effects will appear more frequent as more people are vaccinated. In other words, the rate of side effects remains very low, but it appears to be more frequent.
This is sometimes called the “law of large numbers”.
For example, researchers in Denmark and Norway studied 280,000 recipients of the AstraZeneca/Oxford vaccine between February and March.
They found a rate of 11 excess blood clots per 100,000 vaccinations, indicating a 0.01% risk of blood clots.
This is an extremely low risk level that ordinary people cannot comprehend easily.
Yet, assuming that 6.4 million Malaysians are vaccinated with the AstraZeneca/Oxford vaccine, that means 600 Malaysians may have a risk of developing blood clots.
(The government has arranged to obtain 12.8 million doses of this two-dose vaccine to date.)
However, that number should be compared with the ICU (intensive care unit) hospitalisations due to Covid-19, which are far higher.
We stress again that the benefits and the advantages of the vaccine far outweigh the risks (and in fact, all three authors of this article are already vaccinated).
Nevertheless, the impact of the law of large numbers will be turbocharged by viral news on social media, breathless reporting by media, or weaponised by irresponsible individuals or leaders.
All that sensational reporting on rare side effects and breakthrough infections can impact vaccine confidence. This calls for several policies to be implemented.
Firstly, the risk communications team of the MOH and CITF must consider thoughtful ways to proactively educate the public on breakthrough infections and side effects.
These communication measures must be compassionate (to those who are unlucky enough to suffer breakthrough infections or rare side effects), sensible (to educate without raising panic) and balanced (to inspire Malaysians to get vaccinated).
Secondly, the CITF and National Pharmaceutical Regulatory Agency (NPRA) should convene regular briefings to provide clear information on breakthrough infections and side effects to the media.
They should also consider hosting media-training sessions where experts can train the media on how to interpret (and therefore report) on vaccine statistics.
This training should be reciprocal, with the media training CITF and NPRA on how to report their vaccine statistics in layperson-friendly and easy-to-understand ways, and not the traditional approach of a large mass of numbers and tables.
Thirdly, the MOH must actively surveil for data on breakthrough infections and side effects, instead of the current passive surveillance model.
All collected data must be regularly and transparently provided to Malaysians via interactive dashboards (like those operated by drug regulators in Hong Kong, US or the Pan-American Health Organisation).
One crucial part of vaccine confidence (and trust in government) is data transparency, and no government can complain that their citizens don’t trust them if they don’t share data.
In the ultra long-term, increasing science literacy and public education starting at the primary school level will improve health literacy, vaccine confidence and the ability to understand vaccination statistics among Malaysians.
In the short term, there remains much within the control of the government to communicate vaccination statistics in balanced and thoughtful ways.
Yee Hui Fang is a pharmacist and postgraduate student at the London School of Hygiene and Tropical Medicine in the UK. Dr Khor Swee Kheng is a physician specialising in health policies and global health. Assoc Prof Dr Chan Yoke Fun is a virologist and head of the Department of Medical Microbiology at Universiti Malaya’s Faculty of Medicine. The views expressed here are entirely their own. For more information, email firstname.lastname@example.org.