Even after COVID-19 vaccines become available, nations must offer widespread testing against infections to end the pandemic, World Health Organization Director-General Tedros Adhanom Ghebreyesus said on Friday.
The U.N. health agency has emphasized the importance of testing since the start of the pandemic in March, and Tedros said it also has provided tools for nations to test people effectively because that is an essential part of the strategy needed to control infections. Since early in the year, he said, WHO officials have shipped millions of tests and other diagnostic products worldwide.
"As vaccines are rolled out, testing will continue to play a vital role. Initially, health workers, older people and other at-risk groups will be prioritized for vaccination," he told a regular news briefing. "If you don’t know where the virus is, you can’t stop it. If you don’t know who has the virus, you can’t isolate them, care for them or trace their contacts."
Two types of tests — genetic and antigen — diagnose whether a person has an infection. A third type — an antibody test — shows if a person had COVID-19 previously. Genetic tests, which are considered the most accurate, use a nasal swab or saliva to obtain a lab sample. The turnaround time for results usually ranges from hours to at least a day.
Antigen tests, which are considered less accurate but are faster and less expensive, examine proteins from a nasal swab. Some can provide results in less than an hour. Antibody tests, which use a blood sample to find proteins that our bodies make to stave off infections, help researchers determine the extent of an infected population.
WHO's chief said everyone who needs a test should be able to get one.
"Testing is the spotlight that shows where the virus is," Tedros said. "Investments in testing must be matched by investments in isolation facilities, clinical care, protecting health workers, contact tracing, cluster investigation and supported quarantine."
The great vaccine race
The emphasis on testing comes as drugmakers seek emergency approval to start distributing several promising vaccines before the end of the year or early next year. Several COVID-19 vaccine candidates are being tested globally using tens of thousands of participants, including some that have enough data to ask regulators for emergency use.
U.S. drugmaker Pfizer and its German partner released an analysis showing their shot was 95% effective at preventing COVID-19, while U.S. drugmaker Moderna released an analysis showing its shot was 94.1% effective. Both of those experimental two-dose vaccines use the brand-new messenger RNA or mRNA technology.
Neither of those vaccine candidates were made with the coronavirus itself. Instead, they were made from a synthetic version of genetic code that can program someone’s cells to produce copies of a fragment of the virus that causes the immune system to go on the attack in case the real virus intrudes.
U.K. drugmaker AstraZeneca released an analysis showing its shot was 70% effective, but was 90% effective for participants who got a half dose and then a full dose. The Russian government said its Sputnik V vaccine was 92% effective.