Be realistic over Covid-19 vaccine
By Charles Onyango | February 27th 2021
There are two misconceptions about Covid-19 testing and vaccine that we should all debunk. The first is that we can test our way out of the pandemic. Someone can test negative on Monday, feel sluggish on Tuesday, and go to an event on Wednesday, and unwittingly be spreading the virus. The test result reveals only whether the virus was detectable at the time of sampling.
It does not confirm with absolute certainty that the person hasn’t previously been exposed to the coronavirus, nor does it give assurances against further contact, which could conceivably occur on the way home or even at the testing centre.
What has perhaps been most troubling is that the efficacy of testing on asymptomatic patients, who are nevertheless contagious, remains unclear. As these limitations show, testing alone clearly isn’t enough. Countries and health systems that have largely contained the virus know that for testing to be effective, it must be carried out aggressively and supplemented with an mitigation system.
Social distancing, tech-enabled contact tracing, and broad distribution of personal protective equipment are critical including targeted lockdown measures.
The second misconception is that testing is less important in the wake of vaccines approval. That the distribution of effective vaccines is already underway, and additional ones getting approved, is good news. Based on earlier forecasts of vaccine efficacy and timing, this is the best-case scenario from a development perspective. We should however temper optimism with realistic expectations and an awareness that we will need to employ testing for some time. Public health officials, test manufacturers, public and private clinical laboratories, and health care providers should recognise need for robust testing ability.
The fact is widespread vaccination will likely take years to occur here, and we may even fall short of our initial distribution goals outlined by the MoH. Even with the vaccines’ initial promise, it’s uncertain whether they can prevent asymptomatic spread or for how long they will provide protection.
It’s also unclear if the current vaccines will provide same level of immunity for everybody, or if some demographics, such as children and the elderly, will require additional protections. The skepticism that many among us feel toward the efficacy and safety of vaccines could also hinder national efforts to achieve herd immunity. Thus public health officials have to rely on testing for the foreseeable future.
Although we are already seeing a steady decline in testing volumes this year, we can anticipate a continued need in 2023 and 2024 as the disease enters a more endemic phase. The actual demand levels for testing will be determined by the epidemiology of the coronavirus as it progresses from a pandemic to its endemic phase: the infection and fatality rates, speed of the spread, length of naturally acquired immunity, share of asymptomatic patients, and the continued impact of comorbidities may influence the volume and type of testing needed.
Vaccines will also be an important factor: its features like efficacy of future vaccines, duration of immunity, impact on transmission, and uptake, coupled with the supply chain’s efficacy and our people’s willingness to get vaccinated, will determine demand for testing. The general efficacy of therapeutics and their impact with regard to mild and severe cases may also affect behaviours and people’s willingness to take risks, thereby indirectly influencing disease levels and testing needs. The government policy levers: requiring that individuals provide proof of vaccination, such as screening, will also increase need for a test.
Testing will remain part of a broader strategy to monitor community spread and prevalence of the virus, as well as to protect larger groups. We have to continue screening in public settings such as schools, airports, and sports arenas.
-The writer is a Global Fellow at Moving Worlds Institute
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