By Rafael Castillo M.D.
In last week’s column, we mentioned a group of local doctors who seem to be overenthusiastic about the use of hydroxychloroquine (HCQ) as prophylaxis and treatment for COVID-19.
Amado San Luis of Pasay City asked us if it’s safe to take HCQ for those exposed to someone with COVID-19 symptoms, and were confirmed by swab test to have the virus.
HCQ or any drug is not recommended for prophylaxis treatment. A trial evaluating the use of HCQ in health-care workers seeing COVID-19 patients showed no benefit for preventing the infection.
I was among those who thought the drug might offer the needed remedy for the SARS-CoV-2 virus when it yielded promising results in initial studies. In laboratory studies, it showed it could prevent the replication of the virus—but that didn’t translate well in terms of clinical trial results.
Trials evaluating the efficacy of HCQ in actual COVID-19 patients showed disappointing results. There was even a red-flag signal that it might potentially cause harm, and increase the risk of death in some patients.
Although HCQ has been around for quite some time and has been shown to be effective and fairly safe in most patients with malaria, some forms of arthritis and lupus, it has a potentially serious side effect in patients with heart issues that may lead to sudden cardiac arrest.
Even in those with previously normal hearts, COVID-19 can directly affect the heart and result in inflamed and irritable heart muscles (myocarditis). HCQ can potentially trigger life-threatening arrhythmias in these patients.
The bottom line for HCQ is that the net effect is either neutral (no effect) or slightly toward the harmful side in COVID-19 patients. It’s best to avoid self-medicating with it, and should our doctor prescribe it to us, either for COVID-19 prevention or treatment, let’s ask him first how sure he is.
I’m not that enthusiastic also about the benefit of vaccines for treating COVID-19. I discussed my misgivings on the current front-runners in the vaccine race in previous columns. I see it as tilting the balance, in the same manner that HCQ does, at this point.
Reason to be hopeful
However, Dr. Edsel Maurice Salvana, director of the National Institute of Health of the University of the Philippines and one of the key figures in the local fight against the pandemic, tells us there’s reason to be hopeful about the vaccines now being evaluated.
“Vaccine trials are coming along nicely. Most of the trials are set up as ‘event-driven’ trials. What that means is that instead of a set time frame, the trials will end once a certain number of people get COVID-19, however long that takes.”
He explains that there are two major advantages to this setup of evaluating the vaccines. First is that it will ensure that the number of patients is significant enough to make comparisons between those who were given the vaccine and those given the placebo (inactive substance).
“The problem with set time frames is that if there aren’t enough infections in the time period, the data might not be very meaningful,” says Dr. Salvana.
This was the case in China, when their COVID-19 infections declined and the researchers were unable to come up with the needed numbers.
The second advantage, says Dr. Salvana, is that if the study participants come from areas with super high COVID-19 transmission, like Brazil and India, the researchers can enroll the desired number of patients, get the results faster, and analyze data without having to wait for the set time frame to end.
How effective could these vaccines be?
“The expected efficacy for the first-generation COVID-19 vaccines is targeted to be about 50 to 70 percent with two doses,” says Dr. Salvana.
He quickly adds, however, that while a 50 to 70 percent reduction in COVID-19 risk is a big help, public health measures are still needed to eliminate the virus. “So keep wearing those masks and face shields and observing proper physical distance,” he advises.
At the rate the vaccine trials are going, we may expect to get some preliminary data in the next month or two. I’m not so enthusiastic about it for now, but I join the prayer of everyone that we can soon have a truly effective and safe vaccine.